High severity7.4NVD Advisory· Published Mar 24, 2026· Updated Apr 13, 2026
CVE-2026-4371
CVE-2026-4371
Description
A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.
Affected products
2cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*+ 1 more
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*range: <140.9.0
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*range: <149.0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
3- www.mozilla.org/security/advisories/mfsa2026-23/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-24/nvdVendor Advisory
- bugzilla.mozilla.org/show_bug.cginvdPermissions Required
News mentions
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