Vulnerability · Published Oct 14, 2025 · Assigned by mozilla
CVE-2025-11712An OBJECT tag type attribute overrode browser behavior on web resources without a content-type
Medium 6.1
In plain English
A medium-severity security flaw in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | firefox | 140.4.0-3.el10_0 | ALSA-2025:18154 |
| AlmaLinux:8 | firefox | 140.4.0-3.el8_10.alma.1 | ALSA-2025:18285 |
| AlmaLinux:9 | firefox | 140.4.0-3.el9_6.alma.1 | ALSA-2025:18155 |
| AlmaLinux:9 | firefox-x11 | 140.4.0-3.el9_6.alma.1 | ALSA-2025:18155 |
| AlmaLinux:10 | thunderbird | 140.4.0-2.el10_0.alma.1 | ALSA-2025:18320 |
| AlmaLinux:8 | thunderbird | 140.4.0-2.el8_10.alma.1 | ALSA-2025:18983 |
| AlmaLinux:9 | thunderbird | 140.4.0-2.el9_6.alma.1 | ALSA-2025:18321 |
| Debian:12 | firefox-esr | 140.4.0esr-1~deb12u1 | DSA-6025-1 |
| Debian:12 | firefox-esr | 140.4.0esr-1~deb12u1 | DEBIAN-CVE-2025-11712 |
| Debian:13 | firefox-esr | 140.4.0esr-1~deb13u1 | DEBIAN-CVE-2025-11712 |
| Debian:13 | firefox-esr | 140.4.0esr-1~deb13u1 | DSA-6025-1 |
| Debian:14 | firefox-esr | 140.4.0esr-1 | DEBIAN-CVE-2025-11712 |
| Debian:12 | thunderbird | 1:140.4.0esr-1~deb12u1 | DSA-6040-1 |
| Debian:12 | thunderbird | 1:140.4.0esr-1~deb12u1 | DEBIAN-CVE-2025-11712 |
| Debian:13 | thunderbird | 1:140.4.0esr-1~deb13u1 | DSA-6040-1 |
| Debian:13 | thunderbird | 1:140.4.0esr-1~deb13u1 | DEBIAN-CVE-2025-11712 |
| Debian:14 | thunderbird | 1:140.4.0esr-1 | DEBIAN-CVE-2025-11712 |
| Rocky Linux:10 | firefox | 0:140.4.0-3.el10_0 | RLSA-2025:18154 |
| Rocky Linux:8 | firefox | 0:140.4.0-3.el8_10 | RLSA-2025:18285 |
| Rocky Linux:9 | firefox | 0:140.4.0-3.el9_6 | RLSA-2025:18155 |
| Rocky Linux:10 | thunderbird | 0:140.4.0-2.el10_0 | RLSA-2025:18320 |
| Rocky Linux:8 | thunderbird | 0:140.4.0-2.el8_10 | RLSA-2025:18983 |
| Rocky Linux:9 | thunderbird | 0:140.4.0-2.el9_6 | RLSA-2025:18321 |
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-11712 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-11712 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2025-11712 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2025-11712 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2025-11712 |
| Ubuntu:22.04:LTS | thunderbird | 1:140.7.1+build1-0ubuntu0.22.04.1 | UBUNTU-CVE-2025-11712 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-116 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1979536
- https://www.mozilla.org/security/advisories/mfsa2025-81/
- https://www.mozilla.org/security/advisories/mfsa2025-83/
- https://www.mozilla.org/security/advisories/mfsa2025-84/
- https://www.mozilla.org/security/advisories/mfsa2025-85/
- https://lists.debian.org/debian-lts-announce/2025/10/msg00031.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00015.html