An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://www.mozilla.org/security/advisories/mfsa2026-101/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-102/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-103/ Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 3
- CwesCWE-787 → CWE-787, CWE-122NVD modified 2026-10-16 19:17
- StatusAnalyzed → ModifiedNVD modified 2026-10-16 19:17
- First seenCVSS 6.1 · mozillaNVD modified 2026-10-15 15:03
Affected (CPE criteria) 1
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
References 4
- https://bugzilla.mozilla.org/show_bug.cgi?id=2070267 Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-101/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-102/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-103/ Vendor Advisory