Vulnerability in Mozilla Firefox
CVE-2026-4722
Privilege escalation in the IPC component. This vulnerability was fixed in Firefox 149 and Thunderbird 149.
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
EPSS: 0.004 (35.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 35.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001
Affected products
- Mozilla Firefox — versions 149
- Mozilla Thunderbird — versions 149
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2026-20/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2026-23/
Frequently asked questions
- What is CVE-2026-4722?
- CVE-2026-4722 is a high-severity vulnerability in Mozilla Firefox. CVSS score: 8.8/10. Published 2026-03-24.
- How severe is CVE-2026-4722?
- High severity. CVSS v3 base score is 8.8 out of 10.