Uninitialized memory in the Networking component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.
https://www.mozilla.org/security/advisories/mfsa2026-122/
https://www.mozilla.org/security/advisories/mfsa2026-121/
https://www.mozilla.org/security/advisories/mfsa2026-120/
https://www.mozilla.org/security/advisories/mfsa2026-119/
https://www.mozilla.org/security/advisories/mfsa2026-118/