6.3

CVE-2025-4444: tor Uncontrolled Resource Consumption

CVSS: 6.3v4.0MediumDeferred
AliasesUBUNTU-CVE-2025-4444DEBIAN-CVE-2025-4444openSUSE-SU-2025:15571-1
Published 18-09-2025Last modified 18-09-2025
Open JSON

Vulnerability summary

CVE-2025-4444 is a medium (CVSS 6.3) Uncontrolled Resource Consumption vulnerability in tor. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.7% of scored vulnerabilities.

Overall risk
25/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.47%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1
MGASA-2026-0187

Timeline

  1. 18-09-2025
    PublishedVulnerability first disclosed.
  2. 18-09-2025
    Last modifiedVulnerability information updated.

Description

A security flaw has been discovered in Tor up to 0.4.7.16/0.4.8.17. Impacted is an unknown function of the component Onion Service Descriptor Handler. Performing manipulation results in resource consumption. The attack may be initiated remotely. The attack's complexity is rated as high. The exploitability is considered difficult. Upgrading to version 0.4.8.18 and 0.4.9.3-alpha is recommended to address this issue. It is recommended to upgrade the affected component.

CVSS metrics

10 scores · 4 sources · 4 versions

EPSS trend

Probability

0.47%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

0.00 pp

From 0.47% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.47%

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

Debian1 product
  • tor< 0.4.9.6-0+deb12u1 | < 0.4.9.6-0+deb13u1 | < 0.4.8.21-1
Opensuse1 product
  • tor&distro=openSUSE Tumbleweed< 0.4.8.18-1.1
Ubuntu1 product
  • torAll versions (No fix recorded)

3 vendors · 3 products

References

10 links