CVE Catalog
CVE-2026-4691
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk0.48%
38th percentile - higher than 38% of all known CVEs
Summary
Use-after-free vulnerability in the CSS Parsing and Computation component of Firefox and Thunderbird. The flaw was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Risk Assessment
An attacker could exploit this vulnerability to execute arbitrary code or cause a denial of service, potentially compromising data confidentiality and integrity.
Recommendation
Immediately update Firefox and Thunderbird to the latest versions specified in the advisory.
Original NVD description (English source)
Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.