A malicious page could have used the type attribute of an OBJECT tag to override the default browser behavior when
Source GCVE Database
Not known to be exploited · CVSS 6.1 Medium · fixed in 144 : update affected systems when convenient.
Data as of 29 Oct 2026, 23:57 UTC
- Patch
- Available – fixed in 144, 140.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 14 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
This vulnerability is fixed in Firefox 144, Firefox ESR 140.4, Thunderbird 144, and Thunderbird ESR 140.4. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation steps are required once updated, as the vendor advisory confirms the fix is available.
Description
A vulnerability in Firefox and Thunderbird prior to versions 144 and ESR 140.4 allowed a malicious web page to use the type attribute of an OBJECT tag to override the browser's default behavior when handling web resources served without a content-type header. This behavior could contribute to cross-site scripting (XSS) attacks on sites that improperly serve files without specifying a content-type header. The issue was addressed in Firefox 144 and Thunderbird 144 as well as Firefox ESR 140.4 and Thunderbird ESR 140.4.
References
- nvd.nist.gov/vuln/detail/CVE-2025-11712 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=1979536 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00015.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00031.html (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-81 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-83 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-84 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-85 (opens in a new tab)