CVE-2025-14321: Mozilla Firefox · Vulnerability
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical : upgrade to 146 as a priority.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 146
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 9 Dec 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 146.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
This vulnerability is fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6. Users and administrators should update to these versions or later to remediate the issue. No additional mitigation actions are required beyond applying the official updates provided by Mozilla.
Description
Use-after-free in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 146, Firefox ESR 140.6, Thunderbird 146, and Thunderbird 140.6.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1992760 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-92/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-94/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-95/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-96/ (opens in a new tab)