Vulnerability in Mozilla Firefox
CVE-2025-10531
Mitigation bypass in the Web Compatibility: Tooling component. This vulnerability was fixed in Firefox 143 and Thunderbird 143.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.8% 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: 0.003 · change: 0.000
Affected products
- Mozilla Firefox — versions 143
- Mozilla Thunderbird — versions 143
Weakness classification (CWE)
Public proof-of-concept exploits
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2025-73/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-77/ (Vendor Advisory)
Frequently asked questions
- What is CVE-2025-10531?
- CVE-2025-10531 is a medium-severity vulnerability in Mozilla Firefox, classified under Authentication Bypass Using an Alternate Path or Channel. CVSS score: 5.4/10. Published 2025-09-16.
- How severe is CVE-2025-10531?
- Medium severity. CVSS v3 base score is 5.4 out of 10.
- Is CVE-2025-10531 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.