CVE-2025-11711: Mozilla Firefox · CWE-591
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 144 when convenient.
Data as of 26 Oct 2026, 08:30 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% 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:U/C:N/I:H/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 26 Oct 2026.
What to do
Upgrade Mozilla Firefox to 144.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
A fix for this vulnerability is available and has been incorporated in Firefox 144, Firefox ESR 115.29, Firefox ESR 140.4, Thunderbird 144, and Thunderbird 140.4. Users and administrators should update to these versions or later to remediate the vulnerability. No additional mitigation actions are required beyond applying the official update.
Description
There was a way to change the value of JavaScript Object properties that were supposed to be non-writeable. This vulnerability was fixed in Firefox 144, Firefox ESR 115.29, Firefox ESR 140.4, Thunderbird 144, and Thunderbird 140.4.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1989978 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-81/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-82/ (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)