CVE-2026-44601 Denial of service in Tor

Low 3.7 Published 7 May 2026 Updated 7 May 2026

A double close of a circuit under memory pressure causes Tor clients to crash, resulting in a 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-2026-44601?

CVE-2026-44601 is a low-severity denial of service vulnerability in torproject Tor, published on 7 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Tor before 0.4.9.7, when circuit queue memory pressure exists, can experience a client crash because of a double close of a circuit, aka TROVE-2026-009.

Weakness: CWE-837

Which versions are affected by CVE-2026-44601?

It affects 1 product.

Products include Torproject Tor.

How do I fix CVE-2026-44601?

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-2026-44601 being exploited?

There is no known exploitation of CVE-2026-44601 in the wild and no public exploit code.

Sources

Also known as DEBIAN-CVE-2026-44601, GHSA-fc55-xrcv-x657, UBUNTU-CVE-2026-44601.