9.8

CVE-2025-1942: mozilla firefox Use of Uninitialized Resource

CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2025-1942CGA-cr48-prrx-j6m5CGA-p5f6-458j-q6w8
Published 04-03-2025Last modified 04-06-2026
Open JSON

Vulnerability summary

CVE-2025-1942 is a critical (CVSS 9.8) Use of Uninitialized Resource vulnerability in mozilla firefox. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.48%
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 3 · Related 5
OPENSUSE-SU-2025:14861-1OPENSUSE-SU-2026:11373-1USN-7334-1CGA-RC5F-VPX2-3VXMUSN-7991-1

Timeline

  1. 04-03-2025
    PublishedVulnerability first disclosed.
  2. 04-06-2026
    Last modifiedVulnerability information updated.

Description

When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string. This vulnerability was fixed in Firefox 136 and Thunderbird 136.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.48%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

+0.01 pp

From 0.47% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.48%

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
Mozilla2 products
Wolfi1 product
  • firefox< 136-r0

4 vendors · 14 products

References

8 links