What is CVE-2026-74949?

CVE-2026-74949 is a high-severity vulnerability, classified under Use After Free. CVSS score: 8.8/10. Published 2026-08-18.

How severe is CVE-2026-74949?

High severity. CVSS v3 base score is 8.8 out of 10.

CVE-2026-74949

CVE-2026-74949

Privilege escalation due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Vulnerability class: Use-After-Free

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

CWE-416 — Use After Free

References

security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org
security@mozilla.org

Frequently asked questions

What is CVE-2026-74949?: CVE-2026-74949 is a high-severity vulnerability, classified under Use After Free. CVSS score: 8.8/10. Published 2026-08-18.
How severe is CVE-2026-74949?: High severity. CVSS v3 base score is 8.8 out of 10.