CVE-2026-92240: Mozjs52 · A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged ' ID' response, crashing
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 31 Oct 2026, 08:20 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 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 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmozjs115pkg:deb/ubuntu/mozjs115?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs78pkg:deb/ubuntu/mozjs78?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs91pkg:deb/ubuntu/mozjs91?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability has been fixed in Thunderbird versions 156, 140.16, and 153.3. Users and administrators should upgrade to these or later versions to remediate the issue. No additional mitigation actions are required as the fix is officially released by Mozilla.
Description
CVE-2026-92240 is an out-of-bounds read vulnerability in the IMAP response parser of Thunderbird's mozjs52 component. A malicious or compromised IMAP server can send an untagged '* ID' response to trigger this vulnerability, causing Thunderbird to crash. The vulnerable code path is reachable before user authentication. This issue was fixed in Thunderbird versions 156, 140.16, and 153.3.
References
- nvd.nist.gov/vuln/detail/CVE-2026-92240 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2069113 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-94 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-95 (opens in a new tab)
- ubuntu.com/security/CVE-2026-92240 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-92240 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-94/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-95/ (opens in a new tab)