CVE-2026-2766: mozjs52 · Use After Free
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 27 Oct 2026, 06:42 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Description
Use-after-free in the JavaScript Engine: JIT component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
References
- ubuntu.com/security/CVE-2026-2766 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-2766 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-13/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-15/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2013583 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-13/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-15/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-16/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-17/ (opens in a new tab)