Hard to quantify, but neither Firefox nor Chrome were compromised at Pwn2Own this year. The sandbox architectures are very similar now. Chrome's still ahead in

Hard to quantify, but neither Firefox nor Chrome were compromised at Pwn2Own this year. The sandbox architectures are very similar now. Chrome's still ahead in having a slightly tighter sandbox and already shipping process-per-site, while Mozilla is working hard to catch up on those. Firefox gets a slight advantage from using Rust in some places instead of C++. I'd say Firefox security is still behind Chrome but in practice not by "a lot".