Vulnerability in Mozilla Firefox
CVE-2025-11712
A malicious page could have used the type attribute of an OBJECT tag to override the default browser behavior when encountering a web resource served without a content-type. This could have contributed to an XSS on a site that unsafely serves files without a content-type header. This vulnerability was fixed in Firefox 144, Firefox ESR 140.4, Thunderbird 144, and Thunderbird 140.4.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 17.9% 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 140.4, 144
- Mozilla Thunderbird — versions 140.4, 144
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
- www.mozilla.org/security/advisories/mfsa2025-81/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-83/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-84/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-85/ (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-11712?
- CVE-2025-11712 is a medium-severity vulnerability in Mozilla Firefox, classified under Improper Encoding or Escaping of Output. CVSS score: 6.1/10. Published 2025-10-14.
- How severe is CVE-2025-11712?
- Medium severity. CVSS v3 base score is 6.1 out of 10.