But report [1] says that "Some of these bugs showed evidence of memory corruption...", which implies that majority of these (which includes 271 bugs from Mythos) don't have evidence at all. Do I not understand something?

> For us this is substantial enough evidence to consider it a security vulnerability at that point

Mythos is supposed to be pretty good at writing actual exploits, so (as I understand) there shouldn't be any serious problems with checking if bug is vulnerability or not.

[1] https://www.mozilla.org/en-US/security/advisories/mfsa2026-3...