CVE-2026-124917: Mozjs52 · Sandbox escape due to use-after-free in the Widget: Gtk component
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 9.6 Critical.
Data as of 13 Nov 2026, 22:46 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 9.6 |
|---|
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 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
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
A fix for this vulnerability is available and has been released in Firefox 160, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7. Users and administrators should apply these updates promptly to mitigate the risk. No additional mitigation actions are required beyond applying the official patches.
Description
CVE-2026-124917 is a critical use-after-free vulnerability in the Widget: Gtk component of mozjs52 that allows sandbox escape. This flaw was fixed in Firefox 160, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7. The vulnerability has a high CVSS score of 9.6, indicating it is remotely exploitable without privileges and can lead to complete compromise of confidentiality, integrity, and availability. No known exploits in the wild have been reported. Users should update to the fixed versions to mitigate the risk.
References
- ubuntu.com/security/CVE-2026-124917 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-124917 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-125/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-127/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-129/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2058648 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-125/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-127/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-128/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-129/ (opens in a new tab)