CVE-2026-4684
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk27th percentile - higher than 27% of all known CVEs
Summary
A race condition and use-after-free vulnerability was found in the WebRender component of Firefox and Thunderbird. It is fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
Risk Assessment
An attacker could remotely exploit this vulnerability to execute arbitrary code or crash the browser, compromising user data confidentiality and integrity.
Recommendation
Immediately update Firefox to version 149 or later, and Thunderbird to version 149 or 140.9 depending on the ESR branch used.
Other vulnerabilities in WebRender
See all- CVE-2026-2761Critical
A sandbox escape vulnerability exists in the Graphics: WebRender component of Firefox and Thunderbird. The flaw is fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
- CVE-2026-2760Critical
A sandbox escape vulnerability exists in the WebRender component of Firefox and Thunderbird due to incorrect boundary conditions in graphics handling. The flaw is fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
- CVE-2026-12289High
A privilege escalation vulnerability exists in the Graphics: WebRender component. It was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
- CVE-2026-6750High
A privilege escalation vulnerability exists in the Graphics: WebRender component of Firefox and Thunderbird. It is fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Original NVD description (English source)
Race condition, use-after-free in the Graphics: WebRender component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.