CVE-2025-0240: mozilla firefox Use After Free
CVSS: 4.0v3.1MediumModified
AliasesUBUNTU-CVE-2025-0240DEBIAN-CVE-2025-0240CGA-63mh-8qff-mc2fCGA-9cg2-9vgw-jq8qCGA-6m68-hrgq-mvpgCGA-h6cw-v9f5-3mx3
Published 07-01-2025Last modified 13-04-2026
Vulnerability summary
CVE-2025-0240 is a medium (CVSS 4.0) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.67% chance of exploitation in the next 30 days, higher than 51.2% of scored vulnerabilities.
CVSS score
4.0/10
010
Medium · v3.1 (CVE.org)EPSS score
0.67%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 32 · Related 11DLA-4011-1DLA-4012-1DSA-5839-1DSA-5841-1MGASA-2025-0009MGASA-2025-0010OPENSUSE-SU-2025:14619-1OPENSUSE-SU-2025:14630-1OPENSUSE-SU-2025:14648-1RHSA-2025:0080RHSA-2025:0132RHSA-2025:0133RHSA-2025:0134RHSA-2025:0135RHSA-2025:0136RHSA-2025:0137RHSA-2025:0138RHSA-2025:0144RHSA-2025:0147RHSA-2025:0162RHSA-2025:0165RHSA-2025:0166RHSA-2025:0167RHSA-2025:0275RHSA-2025:0281RHSA-2025:0284RHSA-2025:0286RHSA-2025:0287SUSE-SU-2025:0056-1SUSE-SU-2025:0059-1SUSE-SU-2025:0080-1USN-7191-1CGA-CJC8-4VC9-84HJCGA-FRMG-XRXV-C29QCGA-GQRW-35CH-89H7USN-7991-1
Timeline
- 07-01-2025PublishedVulnerability first disclosed.
- 13-04-2026Last modifiedVulnerability information updated.
Description
Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.
CVSS metrics
6 scores · 6 sources · 1 versionMedium 4.0Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NSourcesAll 6 agree
- OSV · UbuntuEcosystem advisory · calculated4.0MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- OSV · DebianEcosystem advisory · calculated4.0MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- OSV · WolfiEcosystem advisory · calculated4.0MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- OSV · ChainguardEcosystem advisory · calculated4.0MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- NVDNIST4.0MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
0.67%
Chance of exploitation in the next 30 days
Percentile
51%
Versus all other CVEs
30-day change
0.00 pp
From 0.67% on 19-09-2026
19-09-202619-10-2026
EPSS score0.67%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu9 products
- firefox< 134.0+build1-0ubuntu0.20.04.1
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
Chainguard2 products
- firefox< 134.0-r0
- firefox-esr< 128.6.0-r0
Debian2 products
- firefox-esr< 128.6.0esr-1~deb12u1 | < 128.6.0esr-1
- thunderbird< 1:128.6.0esr-1~deb12u1 | < 1:128.6.0esr-1
Mozilla2 products
- firefox< 128.6.0 | < 134.0
- thunderbird< 128.6.0 | ≥ 129.0, < 134.0
Wolfi1 product
- firefox< 134.0-r0
5 vendors · 16 products
