In an out-of-memory scenario an allocation could fail but free would have been called on the pointer afterwards leading to memory corruption. This vulnerability affects Firefox < 128, Firefox ESR < 115.13, Thunderbird < 115.13, and Thunderbird < 128.
https://www.mozilla.org/security/advisories/mfsa2024-32/
https://www.mozilla.org/security/advisories/mfsa2024-31/
https://www.mozilla.org/security/advisories/mfsa2024-30/