VulnerabilityPublished 20 Oct 2026Updated 28 Oct 2026

CVE-2026-113399: Mozjs52 · Incorrect boundary conditions in the SVG component

Affects mozjs52Source GCVE Database

Authoritative record:CVE-2026-113399· Medium

Not known to be exploited · fixed in 158.0.1 : update mozjs52 when convenient.

Data as of 28 Oct 2026, 23:28 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in 158.0.1

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Oct 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 24.04 LTSmozjs102`pkg:deb/ubuntu/mozjs102?arch=source&distro=noble`Other threats	Affected =102.15.1-1 =102.15.1-3ubuntu2	Fixed in–
Ubuntu 24.04 LTSmozjs115`pkg:deb/ubuntu/mozjs115?arch=source&distro=noble`Other threats	Affected 115.3.0-0ubuntu1 – 115.10.0-1 9 affected builds	Fixed in–
Ubuntu 22.04 LTSmozjs102`pkg:deb/ubuntu/mozjs102?arch=source&distro=jammy`Other threats	Affected 102.11.0-0ubuntu0.22.04.1 – 102.15.1-0ubuntu0.22.04.1 4 affected builds	Fixed in–
Ubuntu 22.04 LTSmozjs78`pkg:deb/ubuntu/mozjs78?arch=source&distro=jammy`Other threats	Affected =78.13.0-1 =78.15.0-2 =78.15.0-4ubuntu1	Fixed in–
Ubuntu 22.04 LTSmozjs91`pkg:deb/ubuntu/mozjs91?arch=source&distro=jammy`Other threats	Affected 91.5.1-0ubuntu1 – 91.10.0-0ubuntu1 5 affected builds	Fixed in–
Ubuntu 22.04 LTSthunderbird`pkg:deb/ubuntu/thunderbird?arch=source&distro=jammy`Other threats	Affected 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

A fix for this vulnerability is available in Firefox 158.0.1 and Thunderbird 158.0.1. Users and administrators should update affected software to these versions or later to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-113399 is a vulnerability in the mozjs52 JavaScript engine related to incorrect boundary conditions in the SVG component. This flaw was addressed and fixed in Firefox version 158.0.1 and Thunderbird 158.0.1. The vulnerability has a medium severity impact as assessed by the source data. There are no known exploits in the wild for this issue. The vendor advisory confirms the fix and provides no indication that further mitigation steps are required beyond updating to the fixed versions.

Impact

The vulnerability could allow for memory safety issues or other unintended consequences when handling SVG content, which may affect the security and stability of affected applications. The impact is rated medium by the source data, with Mozilla internally rating it as high. There are no known active exploits in the wild, reducing immediate risk. However, unpatched versions remain vulnerable to potential exploitation.

Summary

The vulnerability identified as CVE-2026-113399 involves incorrect boundary conditions within the SVG component of the mozjs52 engine. This type of flaw can potentially lead to memory safety issues or other unintended behavior when processing SVG content. Mozilla fixed this vulnerability in Firefox 158.0.1 and Thunderbird 158.0.1. The advisory indicates a high impact rating internally, but the source data lists the severity as medium. No public exploit code or active exploitation has been reported. The fix is available and users are advised to update to the patched versions to remediate the issue.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 23:28 UTC

Technical details

References

Community reviews

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