CVE-2025-6424

Published: Jun 24, 2025Modified: Jun 17, 2026

9.8

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitability: 3.9 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Affected (3)

Products: Mozilla: Firefox

Mozilla

1 product

Firefox

Configuration A

3 vulnerable

Vulnerable Software	Affected Versions
Mozilla Firefox	Before 140.0
Mozilla Firefox	Before 115.25.0
Mozilla Firefox	From 116.0 to 128.12.0

Related CWEs

CWE-416

Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

References (8)

https://bugzilla.mozilla.org/show_bug.cgi?id=1966423

Source: security@mozilla.org

Permissions Required

https://www.mozilla.org/security/advisories/mfsa2025-51/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-52/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-53/

Source: security@mozilla.org

Vendor Advisory

https://www.mozilla.org/security/advisories/mfsa2025-54/

Source: security@mozilla.org

https://www.mozilla.org/security/advisories/mfsa2025-55/

Source: security@mozilla.org

https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html

Source: af854a3a-2127-422b-91ae-364da2661108

https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html

Source: af854a3a-2127-422b-91ae-364da2661108

Timeline

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