CVE-2025-6424 — Use After Free in Mozilla Firefox

CWE-416 — Use After Free12 documents8 sources
Severity
9.8CRITICALNVD
EPSS
0.3%
top 46.17%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedJun 24
Latest updateJul 22

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:HExploitability: 3.9 | Impact: 5.9

Affected Packages2 packages

▶NVDmozilla/firefox116.0 — 128.12.0+2
▶Debianmozilla/thunderbird< 1:128.12.0esr-1~deb11u1+3

🔴Vulnerability Details

3
GHSA
GHSA-87c4-94w2-rw7j: A use-after-free in FontFaceSet resulted in a potentially exploitable crash↗2025-06-26
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CVEList
Use-after-free in FontFaceSet↗2025-06-24
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OSV
CVE-2025-6424: A use-after-free in FontFaceSet resulted in a potentially exploitable crash↗2025-06-24
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📋Vendor Advisories

8
Ubuntu
Thunderbird vulnerabilities↗2025-07-22
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Red Hat
firefox: thunderbird: Use-after-free in FontFaceSet↗2025-06-24
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Debian
CVE-2025-6424: firefox - A use-after-free in FontFaceSet resulted in a potentially exploitable crash. Thi...↗2025
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Mozilla
Mozilla Foundation Security Advisory 2025-51: CVE-2025-6424↗
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Mozilla
Mozilla Foundation Security Advisory 2025-52: CVE-2025-6424↗
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CVE-2025-6424 — Use After Free in Mozilla Firefox | cvebase