CVE-2026-118023: Mozjs52 · Sandbox escape due to use-after-free in the Graphics: WebRender component
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 7 Nov 2026, 02:37 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 8.8 |
|---|
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Oct 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 6 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 is available and has been implemented in Firefox 159 and Thunderbird 159. Users and administrators should update affected products to these versions or later to mitigate this vulnerability. No additional mitigation steps are required as the issue is resolved by the official patch.
Description
CVE-2026-118023 is a high-severity use-after-free vulnerability in the Graphics: WebRender component of mozjs52, which can lead to sandbox escape. This flaw was addressed and fixed in Firefox 159 and Thunderbird 159. The vulnerability allows an attacker to potentially break out of the sandbox environment, impacting confidentiality, integrity, and availability.
References
- ubuntu.com/security/CVE-2026-118023 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-118023 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-118/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2079499 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-118/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-121/ (opens in a new tab)