Use After Free in Mozilla Firefox
CVE-2026-6746
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 150, Firefox ESR 115.35, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: -0.000
Affected products
- Mozilla Firefox — versions 115.35, 140.10, 150
- Mozilla Thunderbird — versions 140.10, 150
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2026-30/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-31/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-32/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-33/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-34/ (Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-6746?
- CVE-2026-6746 is a high-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 7.5/10. Published 2026-04-21.
- How severe is CVE-2026-6746?
- High severity. CVSS v3 base score is 7.5 out of 10.