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.
Metrics
CVSS 3.1 7.4/10
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Thunderbird | — |
| Red Hat | Red Hat Enterprise Linux 10 | — |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8 | — |
| Red Hat | Red Hat Enterprise Linux 8.2 Advanced Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Telecommunications Update Service | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9 | — |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | — |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | — |
| Red Hat | Red Hat Enterprise Linux 10 | — |
| Red Hat | Red Hat Enterprise Linux 6 | — |
| Red Hat | Red Hat Enterprise Linux 7 | — |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2023493Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-23/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-24/Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:6188
- https://access.redhat.com/errata/RHSA-2026:6342
- https://access.redhat.com/errata/RHSA-2026:6917
- https://access.redhat.com/errata/RHSA-2026:8284
- https://access.redhat.com/errata/RHSA-2026:8285
- https://access.redhat.com/errata/RHSA-2026:8286
- https://access.redhat.com/errata/RHSA-2026:8287
- https://access.redhat.com/errata/RHSA-2026:8288
- https://access.redhat.com/errata/RHSA-2026:8289
- https://access.redhat.com/errata/RHSA-2026:8290
- https://access.redhat.com/errata/RHSA-2026:8315
- https://access.redhat.com/errata/RHSA-2026:8850
- https://access.redhat.com/security/cve/CVE-2026-4371
- https://bugzilla.redhat.com/show_bug.cgi?id=2451001
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4371.json
Timeline
- Published
- Mar 24, 2026
- Last modified
- Jul 15, 2026
- NVD status
- Modified