Authentication Bypass Affecting rsync package, versions <3.4.3-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.28% (20th percentile)

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  • Snyk IDSNYK-ALPINE321-RSYNC-16780684
  • published21 May 2026
  • disclosed20 May 2026

Introduced: 20 May 2026

CVE-2026-43617  (opens in a new tab)
CWE-289  (opens in a new tab)

How to fix?

Upgrade Alpine:3.21 rsync to version 3.4.3-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rsync package and not the rsync package as distributed by Alpine. See How to fix? for Alpine:3.21 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1