CVE-2025-4444 Tor Onion Service Descriptor resource consumption
Remote attackers can cause resource exhaustion in Tor Onion Service Descriptor Handler, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-4444?
CVE-2025-4444 is a medium-severity denial of service vulnerability in Tor, published on 18 Sep 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-4444?
Linux distribution packages (1)
tor openSUSE:Tumbleweed | All versions | 0.4.8.18-1.1 |
How do I fix CVE-2025-4444?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-4444 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-4444 exists.
Sources
Also known as DEBIAN-CVE-2025-4444, GHSA-qc3c-vmf8-hgcj, UBUNTU-CVE-2025-4444, openSUSE-SU-2025:15571-1.