Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 140.4.0 |
| Mozilla | Thunderbird | < 140.4.0 |
Related Weaknesses (CWE)
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1979536Issue TrackingPermissions Required
- https://www.mozilla.org/security/advisories/mfsa2025-81/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-83/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-84/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2025-85/Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2025/10/msg00015.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00031.html
FAQ
What is CVE-2025-11712?
CVE-2025-11712 is a vulnerability with a CVSS score of 6.1 (MEDIUM). 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 contribute...
How severe is CVE-2025-11712?
CVE-2025-11712 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-11712?
Check the references section above for vendor advisories and patch information. Affected products include: Mozilla Firefox, Mozilla Thunderbird.