CVE-2026-100792: Mozilla Thunderbird · Type Confusion
Affects Mozilla ThunderbirdSource CVE Database V5
Not known to be exploited · CVSS 7.1 High · fixed in 140.17 : patch Mozilla Thunderbird soon.
Data as of 13 Nov 2026, 23:53 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 140.17
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
AI-suggested
The vulnerability has been fixed in Thunderbird versions 140.17, 153.4, and 157. Users and administrators should update to one of these fixed versions to remediate the issue. No additional mitigation actions are specified by the vendor advisory.
Description
CVE-2026-100792 is a high-severity vulnerability in Mozilla Thunderbird involving a JIT miscompilation issue in the JavaScript WebAssembly component. This flaw could lead to high confidentiality impact and limited integrity impact without affecting availability. The vulnerability has been fixed in Thunderbird versions 140.17, 153.4, and 157, as well as corresponding Firefox versions. No known exploits are reported in the wild.
References
- bugzilla.mozilla.org/show_bug.cgi?id=2073266 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-100/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-97/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-99/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-101/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-102/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-103/ (opens in a new tab)