6.5

CVE-2025-4086: mozilla firefox

CVSS: 6.5v3.1MediumModified
AliasesCGA-4mmf-55w8-65hqCGA-827w-rg45-j53xCGA-4mgq-6wr8-x44w
Published 29-04-2025Last modified 13-04-2026
Open JSON

Vulnerability summary

CVE-2025-4086 is a medium (CVSS 6.5) vulnerability in mozilla firefox. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.2% of scored vulnerabilities.

Overall risk
26/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.29%
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 2 · Related 4
OPENSUSE-SU-2025:15045-1OPENSUSE-SU-2026:11373-1CGA-6WRX-4M7P-6QF3UBUNTU-CVE-2025-4086

Timeline

  1. 29-04-2025
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog. *This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.*. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

20%

Versus all other CVEs

30-day change

+0.01 pp

From 0.28% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.29%

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

Chainguard2 products
  • firefox< 138-r0
  • firefox-esr< 138-r0
Mozilla2 products
Wolfi1 product
  • firefox< 138-r0

3 vendors · 5 products

References

3 links