Critical severity · published Jun 24, 2025
CVE-2025-6424
Use-after-free in FontFaceSet
9.8
CVSS
8%
EPSS
No
On KEV
Description
A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)8.0% · higher than 95% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 115.25.0; before 140.0; 116.0 before 128.12.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-6424
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-6424
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=1966423
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-51/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-52/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-53/
www.mozilla.org
https://www.mozilla.org/security/advisories/mfsa2025-54/
www.mozilla.org
https://www.mozilla.org/security/advisories/mfsa2025-55/
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