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.
Does this matter?
Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 0.26% probability · 17th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-116
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1979536Issue Tracking, Permissions 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.