CVE-2025-6424: mozilla firefox Use After Free
CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2025-6424DEBIAN-CVE-2025-6424CGA-92rm-6cr2-mfxxCGA-qwp6-5pj8-mqfjCGA-3hmg-6v65-wxr4CGA-4h8x-j34r-4g6v
Published 24-06-2025Last modified 13-04-2026
Vulnerability summary
CVE-2025-6424 is a critical (CVSS 9.8) Use After Free vulnerability in mozilla firefox. EPSS estimates a 4.39% chance of exploitation in the next 30 days, higher than 91.2% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)EPSS score
4.39%
0%100%
Low · +0.77 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 41 · Related 15DLA-4231-1DLA-4239-1DSA-5950-1DSA-5959-1MGASA-2025-0201MGASA-2025-0228OPENSUSE-SU-2025-20135-1OPENSUSE-SU-2025:15216-1OPENSUSE-SU-2025:15312-1OPENSUSE-SU-2025:15315-1OPENSUSE-SU-2025:15325-1OPENSUSE-SU-2025:20135-1RHSA-2025:10072RHSA-2025:10073RHSA-2025:10074RHSA-2025:10159RHSA-2025:10160RHSA-2025:10161RHSA-2025:10163RHSA-2025:10164RHSA-2025:10165RHSA-2025:10166RHSA-2025:10181RHSA-2025:10182RHSA-2025:10183RHSA-2025:10184RHSA-2025:10185RHSA-2025:10186RHSA-2025:10187RHSA-2025:10188RHSA-2025:10195RHSA-2025:10196RHSA-2025:10246SUSE-SU-2025:02122-1SUSE-SU-2025:02123-1SUSE-SU-2025:02339-1SUSE-SU-2025:02368-1SUSE-SU-2025:02529-1SUSE-SU-2025:02546-1SUSE-SU-2025:21170-1USN-7663-1CGA-P3VV-89X2-7GG4
Timeline
- 24-06-2025PublishedVulnerability first disclosed.
- 13-04-2026Last modifiedVulnerability information updated.
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 metrics
6 scores · 6 sources · 1 versionCritical 9.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 6 agree
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · WolfiEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · ChainguardEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
4.39%
Chance of exploitation in the next 30 days
Percentile
91%
Versus all other CVEs
30-day change
+0.77 pp
From 3.62% on 19-09-2026
19-09-202619-10-2026
EPSS score4.39%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu8 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
Chainguard2 products
- firefox< 128.12-r0
- firefox-esr< 115.25-r0
Debian2 products
- firefox-esr< 128.12.0esr-1~deb12u1 | < 128.12.0esr-1
- thunderbird< 1:128.12.0esr-1~deb12u1 | < 1:128.12.0esr-1
Mozilla1 product
- firefox< 115.25.0 | < 140.0 | ≥ 116.0, < 128.12.0
Wolfi1 product
- firefox< 128.12-r0
5 vendors · 14 products
