CVE-2026-43617

EUVD-2026-31013
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
4.8 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Debian logo
Debian Releases
Debian Product
Codename
rsync
bookworm
vulnerable
bookworm (security)
vulnerable
bullseye
vulnerable
bullseye (security)
vulnerable
forky
vulnerable
sid
3.4.3+ds1-2
fixed
trixie
vulnerable
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://github.com/RsyncProject/rsync/releases/tag/v3.4.3
https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjfm-3w2m-jf4f
https://www.vulncheck.com/advisories/rsync-authorization-bypass-via-hostname-resolution