Skip to main content
VulnerabilityPublished Updated

CVE-2025-0247: Mozilla Firefox

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · 10% EPSS · CVSS 9.8 Critical.

Data as of 26 Oct 2026, 11:07 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 Jan 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Mozilla FirefoxAffected
  • =133
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.

References

Community reviews

Loading reviews…