CVE-2026-103500

EUVD-2026-90200
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mozillaCNA
UNKNOWN
---
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mozillathunderbird
𝑥
< 157
CNA
mozillathunderbird_esr
𝑥
< 140.17
CNA
mozillathunderbird_esr
141.0.0 ≤
𝑥
< 153.4
CNA
References
https://bugzilla.mozilla.org/show_bug.cgi?id=2070267
https://www.mozilla.org/security/advisories/mfsa2026-101/
https://www.mozilla.org/security/advisories/mfsa2026-102/
https://www.mozilla.org/security/advisories/mfsa2026-103/