The author does not seem to mean "the end of langsec" as in "everyone will give up on it", but rather the end of a period characterized, and not incorrectly, by

The author does not seem to mean "the end of langsec" as in "everyone will give up on it", but rather the end of a period characterized, and not incorrectly, by the opinion that a safe programming language guarantees the absence of unintentional unsafe behaviour. In short, that things which, within this "langsec framework", one could prove to be impossible, turn out to be possible in practice; in the author's own words: "The basis of language security is starting from a programming language with a well-defined, easy-to-understand semantics. From there you can prove (formally or informally) interesting security properties about particular programs. [..] But the Spectre and Meltdown attacks have seriously set back this endeavor. One manifestation of the Spectre vulnerability is that code running in a process can now read the entirety of its address space, bypassing invariants of the language in which it is written, even if it is written in a "safe" language. [...] Mathematically, in terms of the semantics of e.g. JavaScript, these attacks should not be possible. But practically, they work. " This is not really news. The limits of formal methods were, in my opinion, well-understood, if often exaggerated by naysayers, brogrammers or simply programmers without much familiarity with them. Intuitively, it is not too difficult to grasp the idea that formal proofs are exactly as solid as the hardware which will run the program about which one is reasoning, and my impression is that it was well-grasped, if begrudgingly, by the community. (This is akin to the well-known mantra that no end-to-end encryption scheme is invulnerable to someone looking over your shoulder and noting what keys you type; similarly, no software-only process isolation scheme is impervious to the hardware looking over its shoulder and "writing down" bytes someplace where everyone can access them)