Use-after-free in the Audio/Video component. This vulnerability was fixed in Firefox 145, Firefox ESR 140.5, Firefox ESR 115.30, Thunderbird 145, and Thunderbird 140.5.
https://www.mozilla.org/security/advisories/mfsa2025-91/
https://www.mozilla.org/security/advisories/mfsa2025-90/
https://www.mozilla.org/security/advisories/mfsa2025-89/
https://www.mozilla.org/security/advisories/mfsa2025-88/