CVE-2025-0247: Mozilla Firefox
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · 10% EPSS · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 10.6% chance of exploitation in 30 days – higher than 95% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 7 Jan 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in– |
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 134 and Thunderbird 134. Users and administrators should upgrade to these versions or later to remediate the issue. Since this is not a cloud service, remediation requires updating the client software. Patch status is confirmed by the vendor advisories at https://www.mozilla.org/security/advisories/mfsa2025-01/ and https://www.mozilla.org/security/advisories/mfsa2025-04/. There are no indications that additional mitigations beyond applying the update are necessary.
Description
Memory safety bugs present in Firefox 133 and Thunderbird 133. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 134 and Thunderbird 134.