CVE-2026-43617

medium

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.

References

https://www.vulncheck.com/advisories/rsync-authorization-bypass-via-hostname-resolution

https://github.com/RsyncProject/rsync/security/advisories/GHSA-rjfm-3w2m-jf4f

https://github.com/RsyncProject/rsync/releases/tag/v3.4.3

Details

Source: Mitre, NVD

Published: 2026-05-20

Updated: 2026-05-20

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 4.8

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Severity: Medium

CVSS v4

Base Score: 6.3

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00026