CVE-2025-4444

Name	CVE-2025-4444
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-6200-1
Debian Bugs	1115744

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
tor (PTS)	bullseye (security), bullseye	0.4.5.16-1	vulnerable
	bookworm	0.4.7.16-1	vulnerable
	bookworm (security)	0.4.9.6-0+deb12u1	fixed
	trixie	0.4.8.16-1	vulnerable
	trixie (security)	0.4.9.6-0+deb13u1	fixed
	forky, sid	0.4.9.6-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
tor	source	bullseye	(unfixed)	end-of-life
tor	source	bookworm	0.4.9.6-0+deb12u1		DSA-6200-1
tor	source	trixie	0.4.9.6-0+deb13u1		DSA-6200-1
tor	source	(unstable)	0.4.8.21-1			1115744

Notes

[bullseye] - tor <end-of-life> (see DSA 5562)
https://github.com/chunmianwang/Tordos
https://forum.torproject.org/t/alpha-and-stable-release-0-4-8-18-and-0-4-9-3-alpha/20578