Home

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 affects Firefox < 144, Firefox ESR < 140.4, Thunderbird < 144, and Thunderbird < 140.4.

PUBLISHED Reserved 2025-10-13 | Published 2025-10-14 | Updated 2025-10-14 | Assigner mozilla

Problem types

An OBJECT tag type attribute overrode browser behavior on web resources without a content-type

Product status

Any version before 144
affected

Any version before 140.4
affected

Any version before 144
affected

Any version before 140.4
affected

Credits

Masato Kinugawa

References

bugzilla.mozilla.org/show_bug.cgi?id=1979536

www.mozilla.org/security/advisories/mfsa2025-81/

www.mozilla.org/security/advisories/mfsa2025-83/

www.mozilla.org/security/advisories/mfsa2025-84/

www.mozilla.org/security/advisories/mfsa2025-85/

cve.org (CVE-2025-11712)

nvd.nist.gov (CVE-2025-11712)

Download JSON