CVE-2025-6424: Mozjs52 · A use-after-free in FontFaceSet resulted in a potentially exploitable crash
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical : upgrade to 1:128.12.0+build1-0ubuntu0.22.04.1 as a priority.
Data as of 28 Oct 2026, 22:28 UTC
- Patch
- Available – fixed in 1:128.12.0+build1-0ubuntu0.22.04.1
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 Jun 2025
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
Upgrade the Ubuntu thunderbird package to 1:128.12.0+build1-0ubuntu0.22.04.1.
Patches and advisories
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
A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
References
- ubuntu.com/security/CVE-2025-6424 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-6424 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2025-51/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2025-53/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1966423 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-51/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-52/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-53/ (opens in a new tab)
- ubuntu.com/security/notices/USN-7663-1 (opens in a new tab)