Internally found bugs present in Firefox ESR 140.13, Firefox ESR 153.0 and Firefox 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Fix
Patch, vendor advisory and mitigation references on NVD 6
- https://www.mozilla.org/security/advisories/mfsa2026-74/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-76/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-77/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-78/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-79/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-80/ Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 5
- CwesCWE-119NVD modified 2026-10-28 17:18
- Cpes+2 CPE criteria (now 2)NVD modified 2026-10-28 17:18
- StatusPublished → ModifiedNVD modified 2026-10-28 17:18
- CVSS9.8 (v3.1, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)NVD modified 2026-10-28 17:18
- First seenunscored · mozillaNVD modified 2026-10-28 16:35
Affected (CPE criteria) 2
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
References 9
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1500946%2C1788109%2C2045379%2C2045380%2C2049339%2C2049393%2C2053580%2C2054662%2C2054665%2C2054673%2C2054785%2C2058645 Broken Link
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048797%2C2050536%2C2053272%2C2053579%2C2057115%2C2057116%2C2057130%2C2057991%2C2057995%2C2058002%2C2058008%2C2058032%2C2058102%2C2058667 Broken Link
- https://bugzilla.mozilla.org/show_bug.cgi?id=2059424 Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-74/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-76/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-77/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-78/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-79/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-80/ Vendor Advisory