Out of bounds read in IMAP parsing (Mozilla Thunderbird)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.37 % · percentile 31 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mozilla
- NVD status
- Modified
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.
Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2023493
- https://www.mozilla.org/security/advisories/mfsa2026-23/
- https://www.mozilla.org/security/advisories/mfsa2026-24/
- 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
- https://access.redhat.com/errata/RHSA-2026:8315
- https://access.redhat.com/errata/RHSA-2026:6342
- https://access.redhat.com/errata/RHSA-2026:6917
- https://access.redhat.com/errata/RHSA-2026:8285
- https://access.redhat.com/errata/RHSA-2026:8850
- https://access.redhat.com/errata/RHSA-2026:8289
- https://access.redhat.com/errata/RHSA-2026:8288
- https://access.redhat.com/errata/RHSA-2026:8286
- https://access.redhat.com/errata/RHSA-2026:8287
- https://access.redhat.com/errata/RHSA-2026:8290
- https://access.redhat.com/errata/RHSA-2026:8284
- https://access.redhat.com/errata/RHSA-2026:6188
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H | CISA-ADP |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H | redhat-SADP |
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 3.1 | HIGH 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
European references
- ENISA EUVD · EUVD-2026-15023
- GCVE · GCVE-0-2026-4371
CERT-FR advisories
- CERTFR-2026-AVI-0354 — Multiples vulnérabilités dans les produits Mozilla · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*< 140.9.0cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*< 149.0
Affected products
| Product | Versions |
|---|---|
| Mozilla · Thunderbird | unaffected 140.9 ≤ 140.* ; unaffected 149 ≤ * |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |