Description
Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. 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 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Affected products
mozilla: firefox; mozilla: thunderbird
References9
- www.mozilla.org/security/advisories/mfsa2026-82/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-84/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-85/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-86/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-87/ Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-88/ Vendor Advisory
- bugzilla.mozilla.org/buglist.cgi?bug_id=2048793%2C2054645%2C205… Issue Tracking
- bugzilla.mozilla.org/buglist.cgi?bug_id=2054631%2C2054657%2C205… Issue Tracking
- bugzilla.mozilla.org/show_bug.cgi?id=2057108 Issue Tracking
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 32 · as of 8 November 2026
- CWE
- CWE-119CWE-200
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