CVE-2026-43617

Name	CVE-2026-43617
Description	Rsync version 3.4.2 and prior contain an authorization bypass vulnerability in the rsync daemon's hostname-based access control list enforcement when configured with chroot. Attackers can bypass hostname-based deny rules by controlling the PTR record for their source IP address, allowing connections from hostnames that administrators intended to deny when reverse DNS resolution fails and defaults to UNKNOWN.
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	DLA-4591-1, DSA-6282-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
rsync (PTS)	bullseye	3.2.3-4+deb11u1	vulnerable
	bullseye (security)	3.2.3-4+deb11u4	fixed
	bookworm	3.2.7-1+deb12u4	vulnerable
	bookworm (security)	3.2.7-1+deb12u5	fixed
	trixie	3.4.1+ds1-5+deb13u2	vulnerable
	trixie (security)	3.4.1+ds1-5+deb13u3	fixed
	forky	3.4.2+ds1-2	vulnerable
	sid	3.4.3+ds1-2	fixed

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

Package	Type	Release	Fixed Version	Origin
rsync	source	bullseye	3.2.3-4+deb11u4	DLA-4591-1
rsync	source	bookworm	3.2.7-1+deb12u5	DSA-6282-1
rsync	source	trixie	3.4.1+ds1-5+deb13u3	DSA-6282-1
rsync	source	(unstable)	3.4.3+ds1-1

https://download.samba.org/pub/rsync/NEWS#3.4.3
https://www.openwall.com/lists/oss-security/2026/05/20/6