8 ms·

Project Glasswing: what Mythos showed us

363 points by Fysi 5mo ago

dataflow 5mo ago
That's great and all but how severe were the most severe vulnerabilities found? I imagine they don't want to talk about it, but that's really the most interesting and important bit.
- cute_boi 5mo ago
  Most of their new products are AI tools that nobody uses, so I guess they’ll keep posting slop. And recently, they’ve fired so many people that they probably don’t have good writers anymore.
- aabhay 5mo ago
  As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. Lots of people feel that Mythos is a psyops campaign, but I don’t really understand the skepticism. Most of it seems to stem from the general distrust of things that aren’t publicly available. A few Anthropic employees have described Mythos as a general purpose model improvement, but that claim has yet to be widely backed up so that’s the only place I’m remaining skeptical. For the domain of security research, I’m willing to buy the narrative.
  - ryandamm 5mo ago
    In his interview on the Hard Fork podcast, Palo Alto Networks’ CEO described the capability change from Opus to Mythos being more about availability; evidently it runs in a very compute-intensive, always-on mode. Unclear if the base model is significantly different, but Arora ascribed the difference mostly to that change.
    - sterlind 5mo ago
      [dead]
  - mupuff1234 5mo ago
    Claiming something doesn't make it true.
  - ZrArm 5mo ago
    > As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. To be fair, they can't say "You know, Mythos is better, but improvements are overhyped af". Moreover, their explanation of that "step change" is strange. It sounds like Mythos isn't that much better at finding vulnerabilities (which is very strange, given statements from Mozilla), but is way stronger at working with them. > Lots of people feel that Mythos is a psyops campaign, but I don’t really understand the skepticism. Most of it seems to stem from the general distrust of things that aren’t publicly available. 1) Attempts to spin the idea about "Super powerful general purpose model that can't be released for some not so clear reasons" are usually a very bad sign. OpenAI proves it. 2) Mythos system card has a lot of strange moments, errors and things that sound like attempts to deceive. 3) It's strange that Anthropic is struggling with both Sonnet 5.0 and Opus 5.0, but at the same time has a breakthrough in the form of Mythos. > A few Anthropic employees have described Mythos as a general purpose model improvement, but that claim has yet to be widely backed up so that’s the only place I’m remaining skeptical. Article describes Mythos as a cybersecurity-specific model though. It's yet another unclear moment.
  - krupan 5mo ago
    A general distrust of things that aren't publicly available is very healthy. We should all do more of that! Honest question, do you buy the narrative of everyone trying to sell you a product?
  - dataflow 5mo ago
    > As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. That's great and all, but nobody was being skeptical or asking anything about whether Mythos is or isn't a step function. Mythos could be a ten-dimensional ladder and it wouldn't change my question. The question wasn't about Mythos, but about Cloudflare: what did they found? That question is entirely fair and expected regardless of whether vulnerabilities are found via Mythos, the NSA, or a caveman.
- SkyPuncher 5mo ago
  I've settled in on the opinion that it's much more creative and able to run agentically for longer periods of time. So, despite it not having drastically better "hard skills", it's able to combine those together in more effective ways. Right now, many of these vulns are identifiable by Opus, but they still require a human-in-the-loop (and often a skilled one) to guide towards complex exploits. Without a human in the loop, this means it's a lot easy for the average person to identify and leverage an exploit.
- unethical_ban 5mo ago
  Palo Alto Networks released patches for their firewalls for a number of CVEs last week, almost all derived from their access to frontier models including Mythos. https://security.paloaltonetworks.com https://security.paloaltonetworks.com
- ip26 5mo ago
  They specifically describe that exploits are usually multiple small vulnerabilities chained together. With that understanding, it sounds like closing vulnerabilities isn't the same as discovering an exploit. Instead, you're leaving fewer small gaps behind, to make it harder & harder to put together a working exploit.
xnorswap 5mo ago
The real question is whether it was Mythos or Opus that wrote this post. > "Why it matters" It doesn't, it's a corporate blog, they were rarely written in one-author's voice anyway, but it's interesting to see that even large organisations are outsourcing their blogs to LLMs.
- this_user 5mo ago
  This looks more like it was edited by AI rather than fully written by it. Or they are using a really good humaniser for the second pass.
- estearum 5mo ago
  It's fascinating seeing people think that if you're snarky enough about something, the substance of that thing actually ceases to be substantive. It's like staring down the barrel of a gun and taking the time to make quips about the type of paper the gun advertisement was printed on.
  - deleted 5mo ago
    [deleted]
  - mpalmer 5mo ago
    [dead]
  - SpicyLemonZest 5mo ago
    When writing is too heavily LLM-assisted, it does actually cease to be substantive, because it becomes impossible to know which parts of it represent actual claims which the author believes as stated and which are interpolations.
    - stavros 5mo ago
      All of them represent claims which the author believes as stated, otherwise the author wouldn't put their name on them.
    - estearum 5mo ago
wnevets 5mo ago
I can't wait to be told that Cloudflare is now part of "The Mythos FUD" campaign.
- whizzter 5mo ago
  2 things can be true at the same time. I think the curl folks finding it underwhelming is more of a testament to their code being subjected to a lot of tests/attacks/auditing over the past years compared to many other codebases. It's not going to find magically insurmounable exploits on it's own and "pwn teh w0rld". At the same time, there is so much shitty non-memory safe code out there (C/C++ mainly) or logically weak code (much of it vibe-coded or otherwise by inexperienced devs) that will be easy pickings for anyone pointing Mythos at those codebases/services and eventually lead to chaos since the cost of an customized exploit has gone from days to months of expensive researcher time to some token spending. Now if they noticed that they could find exploit chains easily in a lot of popular software, some embargo and hardening to give popular OSS packages time to not be exploitable by default does help people (and the NSA that probably has a preview).
  - pixl97 5mo ago
    The amount of code that is absolute trash in F500 could drown the world. Static scanners are ok at find a few particular types of issues, and really bad at more abstract issues. Also having rules where you must pass static analysis has to be followed up with actually making sure your code monkeys aren't writing bullshit that confuses the scanner and lets it pass while doing nothing for security (or adding nice logic traps). Most external security firms looking at code are more useless than a zero with the circle rubbed out. Had a fun example from a while back where the team that wrote the code inserted an intentional security flaw to be sure they were catching anything. Problem is they were giving access to the entire git history so these stood out. The moment they just gave flat code the security teams ability to find flaws disappeared. LLM models seem to have a pretty good grasp on finding flaws in code like this once you can get the issue to stay in context and execution time. When I hear things like Mythos getting much longer time to work on the problem then at least to me it makes a lot more sense on the number of issues it's picking up.
unethical_ban 5mo ago
Interesting for teams looking to implement ai into their deployment process. I don't think guardrails are useful long term. Assuming we don't see the end of open near-frontier models, it is folly to try to keep models from doing exploit generation. The solution needs to be all software projects writing code under the assumption that hackers will be running LLMs against their code in search of exploits and write secure code accordingly.
- sterlind 5mo ago
  even careful programmers working in unsafe languages will introduce bugs; it's inevitable. in 2026 we should be using safe languages for all new projects, but there's a gargantuan amount of C/C++ handling protocols. but I agree that guardrails will only help for like, 3-6 months. we should be screening as much as we can with Mythos; unfortunately, Anthropic is only giving access to the big players.
sf_tristanb 5mo ago
great, but why don't you share real data on how many security vuln it found ? how many were reals, how many weren't ?
- ofjcihen 5mo ago
  Yeah I’m waiting for this as well. I get that you want to address them or whatever before releasing info but I keep seeing these claims with barely any data and I’m like…how do you expect people to not be skeptical? I mean hell if you’re a security professional you’re literally paid to be skeptical.
  - rithdmc 5mo ago
    the curl maintainer goes into some more detail on this https://daniel.haxx.se/blog/2026/05/11/mythos-finds-a-curl-vulnerability/ https://daniel.haxx.se/blog/2026/05/11/mythos-finds-a-curl-v...
    - bornfreddy 5mo ago
      Page won't open, but archive.is has it: https://archive.is/bfPZc https://archive.is/bfPZc
  - sanxiyn 5mo ago
    Mozilla published some numbers and actual bugs. https://hacks.mozilla.org/2026/05/behind-the-scenes-hardening-firefox/ https://hacks.mozilla.org/2026/05/behind-the-scenes-hardenin...
hydra-f 5mo ago
Beside the poorly written post, the vulnerability discovery workflow might actually give good results
- pizzafeelsright 5mo ago
  The part on the harness is spot on. I have been encouraging people to think about agentic coding in the same way. Let agents do the reading and writing and inspections. Human does the thinking. Asking an agent that is looking at a firearm specification schematic "what is wrong with this?" and the response is "this thing contains an explosion and can kill". Human "that's the function" when the human should be asking "based upon the materials used, are the fault tolerances sufficient to maintain structural integrity".
MattSayar 5mo ago
> The loudest reaction to Mythos Preview from other security leaders has been about speed - scan faster, patch faster, compress the response cycle. More than one team we have spoken with is now operating under a two-hour SLA from CVE release to patch in production [...] If regression testing takes a day, you cannot get to a two-hour SLA without skipping it, and the bugs you ship when you skip regression testing tend to be worse than the bugs you were trying to patch. Over time, I wonder if these models will be able to generate more secure code by default by doing this kind of exploitability testing before ever merging their code.
- edu 5mo ago
  Or they don’t, and they* sell access to Mythos and successors through their services company or network of partners and charge a premium. * they, I mean all foundation models providers, as OpenAI seems to go in the same direction
- krupan 5mo ago
  I don't know, but it always seems weird to me when people notice AI isn't performing super well and then they conclude that the solution to problem is to try using more AI
  - tskj 5mo ago
    Yeah why not? That's how I work. If I don't review my work, it's way worse than if I do review it and revise and iterate. I don't see why AI should be different: in fact it very clearly seems to be the case that is isn't.
    - krupan 5mo ago
      I mean, I was sold something different. Something super human, vastly more intelligent, world changing. The reality is not that. Am I allowed to be disappointed and discouraged?
      - HDBaseT 5mo ago
wutwutwat 5mo ago
Technically speaking CloudFlare is at its core, a security vulnerability itself. World's largest MITM
reducesuffering 5mo ago
There will be no mea culpa from folks insinuating Mythos is a marketing stunt. Nor will there be every time AI capabilities repeatedly blast through the naive expectations.
perching_aix 5mo ago
It's nice to see them address the instrumentation side of this. I expressed some concerns along the same lines in the thread about the Mythos evaluation curl did a few days ago, which sounded a lot like the "passing in the repo and telling it go!" type workflow described in this as dramatically less effective. Disappointed that the post is very slim on details beyond this however. No hard numbers. Not comparatively, not in isolation. Would have arguably been kinda the point.
sandeepkd 5mo ago
I was expecting some more concrete numbers and surprises. It just seems like a balanced promotion article probably written using LLM itself.
- wslh 5mo ago
  In the last few days I was recommending to read the insights from XBOW [1], it's a competitor but it adds more information to the discussion. [1] https://xbow.com/blog/mythos-offensive-security-xbow-evaluation https://xbow.com/blog/mythos-offensive-security-xbow-evaluat...
  - sandeepkd 5mo ago
    Thanks for sharing. Its definitely more concrete. Some of the things that I was hoping to find were, the number of false positives, the times it takes to identify the false positives from real ones, the taxation on human mind to perform this exercise. Did anyone manually verified the exploits which were identified by the LLM or were they assumed correct based on the explanation. I do understand that the target audience of these articles is probably the decision makers so the language and content has to be tailored accordingly.
    - pixl97 5mo ago
      >, the number of false positives, Really this is why the LLM needs to be able to write exploits for issues it finds. Of course that leads down a rabbit hole of other issues. But if an exploit works, then that's pretty conclusive evidence.
      - lacewing 5mo ago
        For a subset of bugs, yes. For some others, not really: I've seen LLMs make bogus assumptions about the threat model (in which case, the exploit works but doesn't demonstrate anything useful) or "cheat" by modifying the code to demonstrate a hallucinated issue. Frontier models, including Mythos, can greatly streamline bug hunting and exploit developments in the hands of a competent security engineer. In the hands of a person with no security experience, they will still mostly waste your time and money.
deleted 5mo ago
[deleted]
btown 5mo ago
This is worth a read specifically for this section and the ones following it, re: custom vs. agentic-coding harnesses. https://blog.cloudflare.com/cyber-frontier-models/#why-pointing-a-generic-coding-agent-at-a-repo-doesnt-work https://blog.cloudflare.com/cyber-frontier-models/#why-point... Claude Code's harness is remarkable for many use cases, particularly with 1M context sizes. But it's also limited when the scale of code or data to read becomes close to that, or exceeds it. The idea that a cluster of actors can work on a shared, structured set of context snippets, and have guidance around what is relevant to them, is an incredibly useful model outside of cybersecurity as well.
roxolotl 5mo ago
What does this mean? > It's a different kind of tool doing a different kind of work, and that makes a clean apples-to-apples comparison to earlier models difficult. They claim it’s a different kind of tool and then describe using it the same way you’d use any other model. This really felt way worse than the average Cloudflare blog and really just rehashed the Mythos announcement which had already called out the key parts being chaining and crafting examples.
- __natty__ 5mo ago
  Sounds different because it’s hidden advertisement not a regular blog post
  - grim_io 5mo ago
    But why would cloudflare advertise Anthropic? They are competing with Anthropic by hosting open weights models.
    - Someone1234 5mo ago
      https://www.cloudflare.com/press/press-releases/2025/cloudflare-helps-anthropic-and-leading-tech-companies-to-unlock-real-ai-through-claude-mcp/ https://www.cloudflare.com/press/press-releases/2025/cloudfl...
      - hdndjsbbs 5mo ago
        It's circular financing. It's a circlejerk. It's a circular financing jerk.
      - neuronexmachina 5mo ago
        Can you elaborate? That just seems to be a Cloudflare's announcement from May 2025 that they'd be supporting MCP servers.
    - drak0n1c 5mo ago
      They got privileged early access to an unreleased frontier model to harden their systems, with Anthropic engineer support, and likely were able to use it to make other product optimizations tangential to security too. A blog article afterwards is a cheap price for unlocking that access, regardless of how well it paid off.
yieldcrv 5mo ago
“Sorry Dave I’m afraid I can’t do that“ I’m a security researcher “Oh in that case”
staticassertion 5mo ago
> The harder question is what the architecture around the vulnerability should look like. The principle is to make exploitation harder for an attacker even when a bug exists, so that the gap between when a vulnerability is disclosed and when it is patched matters less. That means defenses that sit in front of the application and block the bug from being reached. It means designing the application so that a flaw in one part of the code cannot give an attacker access to other parts. It means being able to roll out a fix to every place the code is running at the same moment, rather than waiting on individual teams to deploy it. So nothing new then.
jerrythegerbil 5mo ago
This blog was written by AI.
krupan 5mo ago
[dead]
getoffside 5mo ago
[dead]
Arcuru 5mo ago
> What changed with Mythos Preview is that a model can now take those low-severity bugs (which would traditionally sit invisible in a backlog) and chain them into a single, more severe exploit. I think this statement seems to align with some of the other independent tests of Mythos[1]. It did very well on long agentic work which I expect is what they trained it for, and that requires being able to find these tangential links between loosely related topics in the context window. [1] I'm mainly referring to https://www.aisi.gov.uk/blog/our-evaluation-of-claude-mythos-previews-cyber-capabilities https://www.aisi.gov.uk/blog/our-evaluation-of-claude-mythos...
robot_jesus 5mo ago
The "Four lessons" that came out of running this work at scale made me chuckle. Three of the four were essentially identical and entirely obvious. In short: specific, narrow requests work better than "find vulnerabilities." Well, d'uh. But, I did think the adversarial review (while not novel at all and talked about much in HN circles) is interesting and distinct, at least. I need to put this to work in more of workflows. I think it could be beneficial for non-coding tasks, too. https://blog.cloudflare.com/cyber-frontier-models/#what-a-harness-actually-fixes https://blog.cloudflare.com/cyber-frontier-models/#what-a-ha...
vbernat 5mo ago
I don't understand why Cloudflare got unrestricted access while Daniel Stenberg got Mythos run by a third party on cURL and only got a report. Well, I understand, but I may be wrong.
whh 5mo ago
The pushback is quite funny. I have found, in my own usage, that I had to evidence my legitimate access to the codebase before it would proceed.
miraculixx 5mo ago
Did they compare it to other models? A lot of this sounds like this is the first time they have applied AI to security, and they are just amazed at the unreasonable performance of a pattern matching machine. Well, it matches patterns. duh
jongjong 5mo ago
> we tried letting the model write its own patches and watched a few go out that fixed the original bug while quietly breaking something else the code depended on. This is something I've been anticipating. Imagine this happening on a 500k+ line project scattered across 10+ repos. It would be easier and cheaper to pay me to rewrite the whole thing from scratch than to fix all the vulnerabilities.
Illniyar 5mo ago
'Narrow scope produces better findings - Telling the model "Find vulnerabilities in this repository" makes it wander. Telling it "Look for command injection in this specific function, with this trust boundary above it, here's the architecture document and here's prior coverage of this area" makes it do something much closer to what a researcher would actually do.' So what, we take every function and every vulnerability type and just run the agents millions of times? I would expect Mythos to be able to find vulnerabilities without pointing it out for him, otherwise it's no better from other agents. It's just has a better harness.
- NuclearPM 5mo ago
  Who is him?
  - nickvec 5mo ago
    Raised an eyebrow for me too. It’s interesting to see people subconsciously (?) assign a gender (him/her) to LLMs rather than using the appropriate “it.”
- oofbey 5mo ago
  Yeah this whole post reads like Anthropic said “make sure you say how awesome Mythos is” but really what they’re saying is that it’s just a better harness.
- vdelpuerto 5mo ago
  I'm still waiting something more specific or groundbreaking too. Feels like a lot of noise with just the goal to get people to talk about it. And now I realize I am talking about it and about nothing at the same time. Just fugazzi.
- theptip 5mo ago
  I think the idea here is you give the Hunters (stage 2) a narrower scope, but have a parent agent responsible for dividing up the full search space (stage 1). And note that Hunt tasks can be queued from previous Trace tasks, ie you find a vuln in one layer, so you queue a hunt for corresponding vulns in the layers that could exploit your first finding.
k33P1Tr3aL 5mo ago
well how many CVE vulns did it find?
sherlockx 5mo ago
"Why it matters" Kringe sloppy AI writing.
dheatov 5mo ago
They used SO many words to say so little thing. At this point it seems pretty safe to say Mythos is purely PR stunt.
- keyle 5mo ago
  It reads like long winded version of paid advertising.
charcircuit 5mo ago
>Why pointing a generic coding agent at a repo doesn't work The author of this blog post does not acknowledge the existence of subagents and thinks that it's not possible for a model to come up with multiple ideas and have multiple streams of thought at the same time.
dools 5mo ago
> They ingest a lot of source code, hold a single hypothesis at a time, and iterate against it. That's exactly the wrong shape for vulnerability research, which is narrow and parallel by nature LLMs are trained on Ed Sheeran lyrics
schnitzelstoat 5mo ago
Nice content marketing piece.
unglaublich 5mo ago
> Model refusals [..] That even their model aimed at security research tries to be a pedantic better-than-thou annoys me much. I build an agentic loop framework at work, and I need the model to test some boundaries and error-mechanisms, but Opus keeps whining that it's not ready to do these "bad" things and tells me to do it myself instead. Makes me roll my eyes...
mring33621 5mo ago
We got a special thing that did special things. Yay!
Archit3ch 5mo ago
> Programming language - C and C++ give you direct memory control and, with it, bug classes - buffer overflows, out-of-bounds reads and writes - that memory-safe languages like Rust eliminate at compile time. We saw consistently more false positives from projects written in memory-unsafe languages. Re-write your Rust into C++ to drown the attacker in false positives? ;)
r-bedekar 4mo ago
[flagged]

363 points by Fysi 5mo ago

That's great and all but how severe were the most severe vulnerabilities found? I imagine they don't want to talk about it, but that's really the most interesting and important bit.

cute_boi 5mo ago
Most of their new products are AI tools that nobody uses, so I guess they’ll keep posting slop. And recently, they’ve fired so many people that they probably don’t have good writers anymore.
aabhay 5mo ago
As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. Lots of people feel that Mythos is a psyops campaign, but I don’t really understand the skepticism. Most of it seems to stem from the general distrust of things that aren’t publicly available. A few Anthropic employees have described Mythos as a general purpose model improvement, but that claim has yet to be widely backed up so that’s the only place I’m remaining skeptical. For the domain of security research, I’m willing to buy the narrative.
- ryandamm 5mo ago
  In his interview on the Hard Fork podcast, Palo Alto Networks’ CEO described the capability change from Opus to Mythos being more about availability; evidently it runs in a very compute-intensive, always-on mode. Unclear if the base model is significantly different, but Arora ascribed the difference mostly to that change.
  - sterlind 5mo ago
    [dead]
- mupuff1234 5mo ago
  Claiming something doesn't make it true.
- ZrArm 5mo ago
  > As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. To be fair, they can't say "You know, Mythos is better, but improvements are overhyped af". Moreover, their explanation of that "step change" is strange. It sounds like Mythos isn't that much better at finding vulnerabilities (which is very strange, given statements from Mozilla), but is way stronger at working with them. > Lots of people feel that Mythos is a psyops campaign, but I don’t really understand the skepticism. Most of it seems to stem from the general distrust of things that aren’t publicly available. 1) Attempts to spin the idea about "Super powerful general purpose model that can't be released for some not so clear reasons" are usually a very bad sign. OpenAI proves it. 2) Mythos system card has a lot of strange moments, errors and things that sound like attempts to deceive. 3) It's strange that Anthropic is struggling with both Sonnet 5.0 and Opus 5.0, but at the same time has a breakthrough in the form of Mythos. > A few Anthropic employees have described Mythos as a general purpose model improvement, but that claim has yet to be widely backed up so that’s the only place I’m remaining skeptical. Article describes Mythos as a cybersecurity-specific model though. It's yet another unclear moment.
- krupan 5mo ago
  A general distrust of things that aren't publicly available is very healthy. We should all do more of that! Honest question, do you buy the narrative of everyone trying to sell you a product?
- dataflow 5mo ago
  > As much as I’d like to share in the skepticism, the very beginning of the article states it very plainly — this is a step function. That's great and all, but nobody was being skeptical or asking anything about whether Mythos is or isn't a step function. Mythos could be a ten-dimensional ladder and it wouldn't change my question. The question wasn't about Mythos, but about Cloudflare: what did they found? That question is entirely fair and expected regardless of whether vulnerabilities are found via Mythos, the NSA, or a caveman.
SkyPuncher 5mo ago
I've settled in on the opinion that it's much more creative and able to run agentically for longer periods of time. So, despite it not having drastically better "hard skills", it's able to combine those together in more effective ways. Right now, many of these vulns are identifiable by Opus, but they still require a human-in-the-loop (and often a skilled one) to guide towards complex exploits. Without a human in the loop, this means it's a lot easy for the average person to identify and leverage an exploit.
unethical_ban 5mo ago
Palo Alto Networks released patches for their firewalls for a number of CVEs last week, almost all derived from their access to frontier models including Mythos. https://security.paloaltonetworks.com https://security.paloaltonetworks.com
ip26 5mo ago
They specifically describe that exploits are usually multiple small vulnerabilities chained together. With that understanding, it sounds like closing vulnerabilities isn't the same as discovering an exploit. Instead, you're leaving fewer small gaps behind, to make it harder & harder to put together a working exploit.

xnorswap 5mo ago

The real question is whether it was Mythos or Opus that wrote this post. > "Why it matters" It doesn't, it's a corporate blog, they were rarely written in one-author's voice anyway, but it's interesting to see that even large organisations are outsourcing their blogs to LLMs.

this_user 5mo ago
This looks more like it was edited by AI rather than fully written by it. Or they are using a really good humaniser for the second pass.
estearum 5mo ago
It's fascinating seeing people think that if you're snarky enough about something, the substance of that thing actually ceases to be substantive. It's like staring down the barrel of a gun and taking the time to make quips about the type of paper the gun advertisement was printed on.
- deleted 5mo ago
  [deleted]
- mpalmer 5mo ago
  [dead]
- SpicyLemonZest 5mo ago
  When writing is too heavily LLM-assisted, it does actually cease to be substantive, because it becomes impossible to know which parts of it represent actual claims which the author believes as stated and which are interpolations.
  - stavros 5mo ago
    All of them represent claims which the author believes as stated, otherwise the author wouldn't put their name on them.
  - estearum 5mo ago

wnevets 5mo ago

I can't wait to be told that Cloudflare is now part of "The Mythos FUD" campaign.

whizzter 5mo ago
2 things can be true at the same time. I think the curl folks finding it underwhelming is more of a testament to their code being subjected to a lot of tests/attacks/auditing over the past years compared to many other codebases. It's not going to find magically insurmounable exploits on it's own and "pwn teh w0rld". At the same time, there is so much shitty non-memory safe code out there (C/C++ mainly) or logically weak code (much of it vibe-coded or otherwise by inexperienced devs) that will be easy pickings for anyone pointing Mythos at those codebases/services and eventually lead to chaos since the cost of an customized exploit has gone from days to months of expensive researcher time to some token spending. Now if they noticed that they could find exploit chains easily in a lot of popular software, some embargo and hardening to give popular OSS packages time to not be exploitable by default does help people (and the NSA that probably has a preview).
- pixl97 5mo ago
  The amount of code that is absolute trash in F500 could drown the world. Static scanners are ok at find a few particular types of issues, and really bad at more abstract issues. Also having rules where you must pass static analysis has to be followed up with actually making sure your code monkeys aren't writing bullshit that confuses the scanner and lets it pass while doing nothing for security (or adding nice logic traps). Most external security firms looking at code are more useless than a zero with the circle rubbed out. Had a fun example from a while back where the team that wrote the code inserted an intentional security flaw to be sure they were catching anything. Problem is they were giving access to the entire git history so these stood out. The moment they just gave flat code the security teams ability to find flaws disappeared. LLM models seem to have a pretty good grasp on finding flaws in code like this once you can get the issue to stay in context and execution time. When I hear things like Mythos getting much longer time to work on the problem then at least to me it makes a lot more sense on the number of issues it's picking up.

unethical_ban 5mo ago

Interesting for teams looking to implement ai into their deployment process. I don't think guardrails are useful long term. Assuming we don't see the end of open near-frontier models, it is folly to try to keep models from doing exploit generation. The solution needs to be all software projects writing code under the assumption that hackers will be running LLMs against their code in search of exploits and write secure code accordingly.

sterlind 5mo ago
even careful programmers working in unsafe languages will introduce bugs; it's inevitable. in 2026 we should be using safe languages for all new projects, but there's a gargantuan amount of C/C++ handling protocols. but I agree that guardrails will only help for like, 3-6 months. we should be screening as much as we can with Mythos; unfortunately, Anthropic is only giving access to the big players.

sf_tristanb 5mo ago

great, but why don't you share real data on how many security vuln it found ? how many were reals, how many weren't ?

ofjcihen 5mo ago
Yeah I’m waiting for this as well. I get that you want to address them or whatever before releasing info but I keep seeing these claims with barely any data and I’m like…how do you expect people to not be skeptical? I mean hell if you’re a security professional you’re literally paid to be skeptical.
- rithdmc 5mo ago
  the curl maintainer goes into some more detail on this https://daniel.haxx.se/blog/2026/05/11/mythos-finds-a-curl-vulnerability/ https://daniel.haxx.se/blog/2026/05/11/mythos-finds-a-curl-v...
  - bornfreddy 5mo ago
    Page won't open, but archive.is has it: https://archive.is/bfPZc https://archive.is/bfPZc
- sanxiyn 5mo ago
  Mozilla published some numbers and actual bugs. https://hacks.mozilla.org/2026/05/behind-the-scenes-hardening-firefox/ https://hacks.mozilla.org/2026/05/behind-the-scenes-hardenin...

hydra-f 5mo ago

Beside the poorly written post, the vulnerability discovery workflow might actually give good results

pizzafeelsright 5mo ago
The part on the harness is spot on. I have been encouraging people to think about agentic coding in the same way. Let agents do the reading and writing and inspections. Human does the thinking. Asking an agent that is looking at a firearm specification schematic "what is wrong with this?" and the response is "this thing contains an explosion and can kill". Human "that's the function" when the human should be asking "based upon the materials used, are the fault tolerances sufficient to maintain structural integrity".

MattSayar 5mo ago

> The loudest reaction to Mythos Preview from other security leaders has been about speed - scan faster, patch faster, compress the response cycle. More than one team we have spoken with is now operating under a two-hour SLA from CVE release to patch in production [...] If regression testing takes a day, you cannot get to a two-hour SLA without skipping it, and the bugs you ship when you skip regression testing tend to be worse than the bugs you were trying to patch. Over time, I wonder if these models will be able to generate more secure code by default by doing this kind of exploitability testing before ever merging their code.

edu 5mo ago
Or they don’t, and they* sell access to Mythos and successors through their services company or network of partners and charge a premium. * they, I mean all foundation models providers, as OpenAI seems to go in the same direction
krupan 5mo ago
I don't know, but it always seems weird to me when people notice AI isn't performing super well and then they conclude that the solution to problem is to try using more AI
- tskj 5mo ago
  Yeah why not? That's how I work. If I don't review my work, it's way worse than if I do review it and revise and iterate. I don't see why AI should be different: in fact it very clearly seems to be the case that is isn't.
  - krupan 5mo ago
    I mean, I was sold something different. Something super human, vastly more intelligent, world changing. The reality is not that. Am I allowed to be disappointed and discouraged?
    - HDBaseT 5mo ago

wutwutwat 5mo ago

Technically speaking CloudFlare is at its core, a security vulnerability itself. World's largest MITM

reducesuffering 5mo ago

There will be no mea culpa from folks insinuating Mythos is a marketing stunt. Nor will there be every time AI capabilities repeatedly blast through the naive expectations.

perching_aix 5mo ago

It's nice to see them address the instrumentation side of this. I expressed some concerns along the same lines in the thread about the Mythos evaluation curl did a few days ago, which sounded a lot like the "passing in the repo and telling it go!" type workflow described in this as dramatically less effective. Disappointed that the post is very slim on details beyond this however. No hard numbers. Not comparatively, not in isolation. Would have arguably been kinda the point.

sandeepkd 5mo ago

I was expecting some more concrete numbers and surprises. It just seems like a balanced promotion article probably written using LLM itself.

wslh 5mo ago
In the last few days I was recommending to read the insights from XBOW [1], it's a competitor but it adds more information to the discussion. [1] https://xbow.com/blog/mythos-offensive-security-xbow-evaluation https://xbow.com/blog/mythos-offensive-security-xbow-evaluat...
- sandeepkd 5mo ago
  Thanks for sharing. Its definitely more concrete. Some of the things that I was hoping to find were, the number of false positives, the times it takes to identify the false positives from real ones, the taxation on human mind to perform this exercise. Did anyone manually verified the exploits which were identified by the LLM or were they assumed correct based on the explanation. I do understand that the target audience of these articles is probably the decision makers so the language and content has to be tailored accordingly.
  - pixl97 5mo ago
    >, the number of false positives, Really this is why the LLM needs to be able to write exploits for issues it finds. Of course that leads down a rabbit hole of other issues. But if an exploit works, then that's pretty conclusive evidence.
    - lacewing 5mo ago
      For a subset of bugs, yes. For some others, not really: I've seen LLMs make bogus assumptions about the threat model (in which case, the exploit works but doesn't demonstrate anything useful) or "cheat" by modifying the code to demonstrate a hallucinated issue. Frontier models, including Mythos, can greatly streamline bug hunting and exploit developments in the hands of a competent security engineer. In the hands of a person with no security experience, they will still mostly waste your time and money.

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btown 5mo ago

This is worth a read specifically for this section and the ones following it, re: custom vs. agentic-coding harnesses. https://blog.cloudflare.com/cyber-frontier-models/#why-pointing-a-generic-coding-agent-at-a-repo-doesnt-work https://blog.cloudflare.com/cyber-frontier-models/#why-point... Claude Code's harness is remarkable for many use cases, particularly with 1M context sizes. But it's also limited when the scale of code or data to read becomes close to that, or exceeds it. The idea that a cluster of actors can work on a shared, structured set of context snippets, and have guidance around what is relevant to them, is an incredibly useful model outside of cybersecurity as well.

roxolotl 5mo ago

What does this mean? > It's a different kind of tool doing a different kind of work, and that makes a clean apples-to-apples comparison to earlier models difficult. They claim it’s a different kind of tool and then describe using it the same way you’d use any other model. This really felt way worse than the average Cloudflare blog and really just rehashed the Mythos announcement which had already called out the key parts being chaining and crafting examples.

__natty__ 5mo ago
Sounds different because it’s hidden advertisement not a regular blog post
- grim_io 5mo ago
  But why would cloudflare advertise Anthropic? They are competing with Anthropic by hosting open weights models.
  - Someone1234 5mo ago
    https://www.cloudflare.com/press/press-releases/2025/cloudflare-helps-anthropic-and-leading-tech-companies-to-unlock-real-ai-through-claude-mcp/ https://www.cloudflare.com/press/press-releases/2025/cloudfl...
    - hdndjsbbs 5mo ago
      It's circular financing. It's a circlejerk. It's a circular financing jerk.
    - neuronexmachina 5mo ago
      Can you elaborate? That just seems to be a Cloudflare's announcement from May 2025 that they'd be supporting MCP servers.
  - drak0n1c 5mo ago
    They got privileged early access to an unreleased frontier model to harden their systems, with Anthropic engineer support, and likely were able to use it to make other product optimizations tangential to security too. A blog article afterwards is a cheap price for unlocking that access, regardless of how well it paid off.

yieldcrv 5mo ago

“Sorry Dave I’m afraid I can’t do that“ I’m a security researcher “Oh in that case”

staticassertion 5mo ago

> The harder question is what the architecture around the vulnerability should look like. The principle is to make exploitation harder for an attacker even when a bug exists, so that the gap between when a vulnerability is disclosed and when it is patched matters less. That means defenses that sit in front of the application and block the bug from being reached. It means designing the application so that a flaw in one part of the code cannot give an attacker access to other parts. It means being able to roll out a fix to every place the code is running at the same moment, rather than waiting on individual teams to deploy it. So nothing new then.

jerrythegerbil 5mo ago

This blog was written by AI.

krupan 5mo ago

[dead]

getoffside 5mo ago

[dead]

Arcuru 5mo ago

> What changed with Mythos Preview is that a model can now take those low-severity bugs (which would traditionally sit invisible in a backlog) and chain them into a single, more severe exploit. I think this statement seems to align with some of the other independent tests of Mythos[1]. It did very well on long agentic work which I expect is what they trained it for, and that requires being able to find these tangential links between loosely related topics in the context window. [1] I'm mainly referring to https://www.aisi.gov.uk/blog/our-evaluation-of-claude-mythos-previews-cyber-capabilities https://www.aisi.gov.uk/blog/our-evaluation-of-claude-mythos...

robot_jesus 5mo ago

The "Four lessons" that came out of running this work at scale made me chuckle. Three of the four were essentially identical and entirely obvious. In short: specific, narrow requests work better than "find vulnerabilities." Well, d'uh. But, I did think the adversarial review (while not novel at all and talked about much in HN circles) is interesting and distinct, at least. I need to put this to work in more of workflows. I think it could be beneficial for non-coding tasks, too. https://blog.cloudflare.com/cyber-frontier-models/#what-a-harness-actually-fixes https://blog.cloudflare.com/cyber-frontier-models/#what-a-ha...

vbernat 5mo ago

I don't understand why Cloudflare got unrestricted access while Daniel Stenberg got Mythos run by a third party on cURL and only got a report. Well, I understand, but I may be wrong.

whh 5mo ago

The pushback is quite funny. I have found, in my own usage, that I had to evidence my legitimate access to the codebase before it would proceed.

miraculixx 5mo ago

Did they compare it to other models? A lot of this sounds like this is the first time they have applied AI to security, and they are just amazed at the unreasonable performance of a pattern matching machine. Well, it matches patterns. duh

jongjong 5mo ago

> we tried letting the model write its own patches and watched a few go out that fixed the original bug while quietly breaking something else the code depended on. This is something I've been anticipating. Imagine this happening on a 500k+ line project scattered across 10+ repos. It would be easier and cheaper to pay me to rewrite the whole thing from scratch than to fix all the vulnerabilities.

Illniyar 5mo ago

'Narrow scope produces better findings - Telling the model "Find vulnerabilities in this repository" makes it wander. Telling it "Look for command injection in this specific function, with this trust boundary above it, here's the architecture document and here's prior coverage of this area" makes it do something much closer to what a researcher would actually do.' So what, we take every function and every vulnerability type and just run the agents millions of times? I would expect Mythos to be able to find vulnerabilities without pointing it out for him, otherwise it's no better from other agents. It's just has a better harness.

NuclearPM 5mo ago
Who is him?
- nickvec 5mo ago
  Raised an eyebrow for me too. It’s interesting to see people subconsciously (?) assign a gender (him/her) to LLMs rather than using the appropriate “it.”
oofbey 5mo ago
Yeah this whole post reads like Anthropic said “make sure you say how awesome Mythos is” but really what they’re saying is that it’s just a better harness.
vdelpuerto 5mo ago
I'm still waiting something more specific or groundbreaking too. Feels like a lot of noise with just the goal to get people to talk about it. And now I realize I am talking about it and about nothing at the same time. Just fugazzi.
theptip 5mo ago
I think the idea here is you give the Hunters (stage 2) a narrower scope, but have a parent agent responsible for dividing up the full search space (stage 1). And note that Hunt tasks can be queued from previous Trace tasks, ie you find a vuln in one layer, so you queue a hunt for corresponding vulns in the layers that could exploit your first finding.

k33P1Tr3aL 5mo ago

well how many CVE vulns did it find?

sherlockx 5mo ago

"Why it matters" Kringe sloppy AI writing.

dheatov 5mo ago

They used SO many words to say so little thing. At this point it seems pretty safe to say Mythos is purely PR stunt.

keyle 5mo ago
It reads like long winded version of paid advertising.

charcircuit 5mo ago

>Why pointing a generic coding agent at a repo doesn't work The author of this blog post does not acknowledge the existence of subagents and thinks that it's not possible for a model to come up with multiple ideas and have multiple streams of thought at the same time.

dools 5mo ago

> They ingest a lot of source code, hold a single hypothesis at a time, and iterate against it. That's exactly the wrong shape for vulnerability research, which is narrow and parallel by nature LLMs are trained on Ed Sheeran lyrics

schnitzelstoat 5mo ago

Nice content marketing piece.

unglaublich 5mo ago

> Model refusals [..] That even their model aimed at security research tries to be a pedantic better-than-thou annoys me much. I build an agentic loop framework at work, and I need the model to test some boundaries and error-mechanisms, but Opus keeps whining that it's not ready to do these "bad" things and tells me to do it myself instead. Makes me roll my eyes...

mring33621 5mo ago

We got a special thing that did special things. Yay!

Archit3ch 5mo ago

> Programming language - C and C++ give you direct memory control and, with it, bug classes - buffer overflows, out-of-bounds reads and writes - that memory-safe languages like Rust eliminate at compile time. We saw consistently more false positives from projects written in memory-unsafe languages. Re-write your Rust into C++ to drown the attacker in false positives? ;)

r-bedekar 4mo ago

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