CVE-2026-100777
CVE-2026-100777
Use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.
Vulnerability class: Use-After-Free
Published · last modified .
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.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi
- www.mozilla.org/security/advisories/mfsa2026-100/
- www.mozilla.org/security/advisories/mfsa2026-97/
- www.mozilla.org/security/advisories/mfsa2026-98/
- www.mozilla.org/security/advisories/mfsa2026-99/
- www.mozilla.org/security/advisories/mfsa2026-101/
- www.mozilla.org/security/advisories/mfsa2026-102/
- www.mozilla.org/security/advisories/mfsa2026-103/
Frequently asked questions
- What is CVE-2026-100777?
- CVE-2026-100777 is a high-severity vulnerability, classified under Use After Free. CVSS score: 8.8/10. Published 2026-09-29.
- How severe is CVE-2026-100777?
- High severity. CVSS v3 base score is 8.8 out of 10.