CVE-2026-4691

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-4691
Use-after-free in the CSS Parsing and Computation component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.

9.8 /10

CVSS v3 : CRITICAL

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=2017512 Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-20/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-21/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-22/ Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-23/
https://www.mozilla.org/security/advisories/mfsa2026-24/
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
History

26 Mar 2026, 13:16

Type Values Removed Values Added
Summary
  • (es) Uso después de liberación en el componente de análisis y computación CSS. Esta vulnerabilidad afecta a Firefox &lt; 149, Firefox ESR &lt; 115.34, Firefox ESR &lt; 140.9, Thunderbird &lt; 149, y Thunderbird &lt; 140.9.

24 Mar 2026, 21:16

Type Values Removed Values Added
Summary (en) Use-after-free in the CSS Parsing and Computation component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, and Firefox ESR < 140.9. (en) Use-after-free in the CSS Parsing and Computation component. This vulnerability affects Firefox < 149, Firefox ESR < 115.34, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
References
  • () https://www.mozilla.org/security/advisories/mfsa2026-23/ -
  • () https://www.mozilla.org/security/advisories/mfsa2026-24/ -

24 Mar 2026, 19:17

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 9.8
CPE cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
First Time Mozilla
Mozilla firefox
CWE CWE-416
References () https://bugzilla.mozilla.org/show_bug.cgi?id=2017512 - () https://bugzilla.mozilla.org/show_bug.cgi?id=2017512 - Permissions Required
References () https://www.mozilla.org/security/advisories/mfsa2026-20/ - () https://www.mozilla.org/security/advisories/mfsa2026-20/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-21/ - () https://www.mozilla.org/security/advisories/mfsa2026-21/ - Vendor Advisory
References () https://www.mozilla.org/security/advisories/mfsa2026-22/ - () https://www.mozilla.org/security/advisories/mfsa2026-22/ - Vendor Advisory

24 Mar 2026, 13:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-03-24 13:16

Updated : 2026-03-26 13:16

NVD link : CVE-2026-4691

Mitre link : CVE-2026-4691

CVE.ORG link : CVE-2026-4691

JSON object : View

Products Affected

mozilla

  • firefox
CWE
CWE-416

Use After Free