CVE-2025-6424
CRITICALCVSS 9.8/10EPSS 3.06%
Last modified
CVE-2025-6424 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 3.06% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | < 115.25.0 |
| Mozilla | Firefox | < 140.0 |
| Mozilla | Firefox | >= 116.0, < 128.12.0 |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1966423Permissions Required
- 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/Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2025-6424?
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.
How severe is CVE-2025-6424?
CVE-2025-6424 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 3.06% probability of exploitation in the next 30 days.
How do I fix CVE-2025-6424?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
Are you affected by CVE-2025-6424?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST