CVE-2025-6424

Use-after-free in FontFaceSet

Published Jun 24, 2025 CVSS 3.1 · 9.8 Critical EPSS 7.9% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Debian DLA Debian DLA DLA-4231-1 firefox-esr security update
Debian DLA Debian DLA DLA-4239-1 thunderbird security update
Debian DSA Debian DSA DSA-5950-1 firefox-esr security update
Debian DSA Debian DSA DSA-5959-1 thunderbird security update
EUVD EUVD EUVD-2025-19086 A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability affects Firefox < 140, Firefox ESR < 115.25, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.
Ubuntu USN Ubuntu USN USN-7663-1 Thunderbird vulnerabilities
History
Type Values Removed Values Added
Description A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability affects Firefox < 140, Firefox ESR < 115.25, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12. 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.
Type Values Removed Values Added
Title firefox: thunderbird: Use-after-free in FontFaceSet Use-after-free in FontFaceSet
Type Values Removed Values Added
Metrics epss

{'score': 0.00076}

epss

{'score': 0.00092}

Type Values Removed Values Added
Title firefox: Use-after-free in FontFaceSet firefox: thunderbird: Use-after-free in FontFaceSet
Type Values Removed Values Added
Description A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability affects Firefox < 140, Firefox ESR < 115.25, and Firefox ESR < 128.12. A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability affects Firefox < 140, Firefox ESR < 115.25, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.
References
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
First Time appeared Redhat rhel Aus
Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
Redhat rhel Tus
CPEs cpe:/a:redhat:enterprise_linux:9
cpe:/a:redhat:rhel_aus:8.2
cpe:/a:redhat:rhel_aus:8.4
cpe:/a:redhat:rhel_aus:8.6
cpe:/a:redhat:rhel_e4s:8.6
cpe:/a:redhat:rhel_e4s:8.8
cpe:/a:redhat:rhel_e4s:9.0
cpe:/a:redhat:rhel_e4s:9.2
cpe:/a:redhat:rhel_eus:9.4
cpe:/a:redhat:rhel_tus:8.6
cpe:/a:redhat:rhel_tus:8.8
cpe:/o:redhat:enterprise_linux:10.0
cpe:/o:redhat:rhel_els:7
Vendors & Products Redhat rhel Aus
Redhat rhel E4s
Redhat rhel Els
Redhat rhel Eus
Redhat rhel Tus
Type Values Removed Values Added
First Time appeared Redhat
Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:8
Vendors & Products Redhat
Redhat enterprise Linux
Type Values Removed Values Added
Weaknesses CWE-416
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Title firefox: Use-after-free in FontFaceSet
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

threat_severity

Important

Type Values Removed Values Added
Description A use-after-free in FontFaceSet resulted in a potentially exploitable crash. This vulnerability affects Firefox < 140, Firefox ESR < 115.25, and Firefox ESR < 128.12.
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
Apr 13, 2026, 2:26 PM
Reserved
Jun 20, 2025, 2:51 PM
Status
Modified
Published
Jun 24, 2025, 1:15 PM
Modified
Oct 23, 2026, 10:10 PM
Severity
Important
Public date
Jun 24, 2025, 12:27 PM