Sometimes, when invalidating JIT code while following an iterator, the newly generated code could be overwritten incorrectly. This could lead to a potentially exploitable crash. This vulnerability affects Firefox < 111, Firefox ESR < 102.9, and Thunderbird < 102.9.
https://www.mozilla.org/security/advisories/mfsa2023-11/
https://www.mozilla.org/security/advisories/mfsa2023-10/