5.3

CVE-2025-0238: mozilla firefox Use After Free

CVSS: 5.3v3.1MediumModified
AliasesUBUNTU-CVE-2025-0238DEBIAN-CVE-2025-0238CGA-vfvp-5wc5-j2q8
Published 07-01-2025Last modified 13-04-2026

Vulnerability summary

CVE-2025-0238 is a medium (CVSS 5.3) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 55.6% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.79%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 33 · Related 11

Timeline

  1. 07-01-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

Assuming a controlled failed memory allocation, an attacker could have caused a use-after-free, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Firefox ESR 115.19, Thunderbird 134, and Thunderbird 128.6.

CVSS metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.79%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

-0.02 pp

From 0.81% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.79%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected 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
Wolfi1 product
  • firefox< 134.0-r0

5 vendors · 16 products

References

14 links
Show all 14 references