CVE-2025-6424

9.8 CRITICAL

Published: June 24, 2025 Modified: April 13, 2026

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.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

CVSS v3.x Details

0.0 Low Medium High Critical 10.0

Vector String

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

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory

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

8 reference(s) from NVD

Quick Stats

CVSS v3 Score

9.8 / 10.0

EPSS (Exploit Probability)

0.3%

54th percentile

Exploitation Status

Not in CISA KEV

Weaknesses (CWE)

CWE-416

Affected Vendors

mozilla

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