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Critical 9.8Published Sep 15, 2026
CVE-2026-92238Ambiguous parsing of mail headers
Updated under an hour ago ()
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It affects Mozilla Thunderbird. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
- CVSS
- 9.8 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-444
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Analyzed
- Record last updated
- Sep 22, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mozilla Thunderbird mozilla:thunderbird (from the name) | 140.16 builds before 140.* not affected; 153.3 builds before 153.* not affected; from 156 not affected | CNA record |
mozilla thunderbird mozilla:thunderbird | before 140.16.0; from 141.0 before 153.3.0; from 154.0 before 156.0 | NVD |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2060601permissions-required
- https://www.mozilla.org/security/advisories/mfsa2026-94/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-95/vendor-advisory
- https://www.mozilla.org/security/advisories/mfsa2026-96/vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.