7.5

CVE-2025-1931: mozilla firefox Use After Free

CVSS: 7.5v3.1HighModified
AliasesUBUNTU-CVE-2025-1931DEBIAN-CVE-2025-1931CGA-6435-29p3-mg47
Published 04-03-2025Last modified 13-04-2026

Vulnerability summary

CVE-2025-1931 is a high (CVSS 7.5) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.2% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.54%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 25 · Related 10

Timeline

  1. 04-03-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability was fixed in Firefox 136, Firefox ESR 115.21, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

CVSS metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.54%

Chance of exploitation in the next 30 days

Percentile

44%

Versus all other CVEs

30-day change

+0.01 pp

From 0.53% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.54%

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< 136.0+build3-0ubuntu0.20.04.1
  • mozjs102All versions (No fix recorded)
  • mozjs115All versions (No fix recorded)
  • mozjs38All versions (No fix recorded)
  • mozjs52All versions (No fix recorded)
Chainguard2 products
  • firefox< 136-r0
  • firefox-esr< 136-r0
Debian2 products
  • firefox-esr< 128.8.0esr-1~deb12u1 | < 128.8.0esr-1
  • thunderbird< 1:128.8.0esr-1~deb12u1 | < 1:128.8.0esr-1
Mozilla2 products
  • firefox< 115.21.0 | < 136.0 | ≥ 116.0, < 128.8.0
  • thunderbird< 128.8.0 | ≥ 129.0, < 136.0
Wolfi1 product
  • firefox< 136-r0

5 vendors · 16 products

References

14 links
Show all 14 references