CVE-2025-11712: Mozilla Firefox · Vulnerability
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 6.1 Medium : upgrade to 144 when convenient.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 144
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
Weaponised: 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 2026-10-26.
What to do
Upgrade Mozilla Firefox to 144.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 144 and Firefox ESR 140.4. Users and administrators should update to these versions or later to remediate the issue. Since this is a client-side browser vulnerability, applying the official browser updates is the primary and recommended mitigation. No additional vendor-recommended mitigations are specified.
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.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1979536 (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)
- lists.debian.org/debian-lts-announce/2025/10/msg00031.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00015.html (opens in a new tab)