Detections
Analytics
CVE-2026-4371
high
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.
References
https://www.mozilla.org/security/advisories/mfsa2026-24/
https://www.mozilla.org/security/advisories/mfsa2026-23/
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4371.json
https://bugzilla.redhat.com/show_bug.cgi?id=2451001
https://bugzilla.mozilla.org/show_bug.cgi?id=2023493
https://access.redhat.com/security/cve/CVE-2026-4371
https://access.redhat.com/errata/RHSA-2026:8850
https://access.redhat.com/errata/RHSA-2026:8315
https://access.redhat.com/errata/RHSA-2026:8290
https://access.redhat.com/errata/RHSA-2026:8289
https://access.redhat.com/errata/RHSA-2026:8288
https://access.redhat.com/errata/RHSA-2026:8287
https://access.redhat.com/errata/RHSA-2026:8286
https://access.redhat.com/errata/RHSA-2026:8285
https://access.redhat.com/errata/RHSA-2026:8284
https://access.redhat.com/errata/RHSA-2026:6917