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VulnerabilityPublished Updated

CVE-2026-109705: Mozjs52 · Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free

Affects mozjs52Source GCVE Database

0
Authoritative record:CVE-2026-109705· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical.

Data as of 29 Oct 2026, 00:13 UTC

CVSS 3.1 base score
9.6Critical
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 24.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=nobleOther threatsAffected
  • =102.15.1-1
  • =102.15.1-3ubuntu2
Fixed in–
Ubuntu 24.04 LTSmozjs115pkg:deb/ubuntu/mozjs115?arch=source&distro=nobleOther threatsAffected
  • 115.3.0-0ubuntu1 – 115.10.0-1
9 affected builds
Fixed in–
Ubuntu 22.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=jammyOther threatsAffected
  • 102.11.0-0ubuntu0.22.04.1 – 102.15.1-0ubuntu0.22.04.1
4 affected builds
Fixed in–
Ubuntu 22.04 LTSmozjs78pkg:deb/ubuntu/mozjs78?arch=source&distro=jammyOther threatsAffected
  • =78.13.0-1
  • =78.15.0-2
  • =78.15.0-4ubuntu1
Fixed in–
Ubuntu 22.04 LTSmozjs91pkg:deb/ubuntu/mozjs91?arch=source&distro=jammyOther threatsAffected
  • 91.5.1-0ubuntu1 – 91.10.0-0ubuntu1
5 affected builds
Fixed in–
Ubuntu 22.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=jammyOther threatsAffected
  • 1:91.1.2+build1-0ubuntu1 – 1:140.7.1+build1-0ubuntu0.22.04.1
39 affected builds
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 Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5. Users and administrators should apply these updates to remediate the issue. No additional mitigation steps are required beyond applying the official patches.

Description

CVE-2026-109705 is a critical vulnerability in the mozjs52 component affecting Firefox, Firefox ESR, and Thunderbird. It involves a sandbox escape and site isolation issue caused by incorrect boundary conditions and a use-after-free flaw in the Networking component. This vulnerability allows an attacker to potentially bypass sandbox restrictions, leading to high impact on confidentiality, integrity, and availability. The issue was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

References

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