Mozjs52: [Unknown description] (CVE-2026-84135)
Description
CVE-2026-84135 is a security vulnerability affecting multiple specific versions of the mozjs52 JavaScript engine used in various Ubuntu LTS releases. The CVSS 3.1 score is 9.8, indicating critical severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. The exact technical details of this vulnerability are not provided in the source data. Mozilla has fixed this and related vulnerabilities in Firefox 155, indicating an official patch is available. There are no known exploits in the wild at this time.
CVSS v3.1
Score 9.8critical
Affected software
pkg:deb/ubuntu/mozjs52?arch=source&distro=bionicpkg:deb/ubuntu/mozjs38?arch=source&distro=bionicpkg:deb/ubuntu/mozjs68?arch=source&distro=focalpkg:deb/ubuntu/mozjs52?arch=source&distro=focalpkg:deb/ubuntu/mozjs102?arch=source&distro=jammypkg:deb/ubuntu/mozjs78?arch=source&distro=jammypkg:deb/ubuntu/mozjs91?arch=source&distro=jammypkg:deb/ubuntu/thunderbird?arch=source&distro=jammypkg:deb/ubuntu/mozjs102?arch=source&distro=noblepkg:deb/ubuntu/mozjs115?arch=source&distro=nobleRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-84135 is a critical security vulnerability in the mozjs52 JavaScript engine component used in multiple Ubuntu LTS versions. Although the specific nature of the vulnerability is not described, the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) indicates it can be exploited remotely without privileges or user interaction, causing complete compromise of confidentiality, integrity, and availability. Mozilla fixed this vulnerability in Firefox 155 as part of a broad security update addressing multiple internally found bugs with memory corruption or other security-relevant defects. The vulnerability affects many exact package versions listed, spanning Ubuntu 18.04, 20.04, 22.04, and 24.04 LTS releases.
Potential Impact
Successful exploitation of CVE-2026-84135 could allow an unauthenticated remote attacker to fully compromise the affected system's confidentiality, integrity, and availability. Given the high CVSS score and vector, this vulnerability poses a critical risk if left unpatched. However, no active exploitation in the wild has been reported. The vulnerability affects multiple Ubuntu LTS versions, potentially impacting a wide user base until updated.
Mitigation Recommendations
Mozilla has released an official fix for this vulnerability in Firefox 155. Users and administrators should update to Firefox 155 or later to remediate this issue. Since this is not a cloud service, patching the affected software versions is required. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-84135
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6a9c2595acd9273b49fbdf3d
Added to database: 09/05/2026, 14:22:13 UTC
Last enriched: 09/07/2026, 14:55:12 UTC
Last updated: 10/20/2026, 06:48:19 UTC
Views: 40
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