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.
Published: 2026-05-20
Score: 6.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

No remediation available yet.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Debian DLA Debian DLA DLA-4591-1 rsync security update
Debian DSA Debian DSA DSA-6282-1 rsync security update
Ubuntu USN Ubuntu USN USN-8283-1 rsync vulnerabilities
History

Wed, 20 May 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 20 May 2026 11:45:00 +0000

Type Values Removed Values Added
First Time appeared Rsync Project
Rsync Project rsync
Vendors & Products Rsync Project
Rsync Project rsync

Wed, 20 May 2026 01:30:00 +0000

Type Values Removed Values Added
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.
Title Rsync < 3.4.3 Authorization Bypass via Hostname Resolution
Weaknesses CWE-289
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

cvssV4_0

{'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'}


Subscriptions

Rsync Project Rsync
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-05-20T15:45:40.806Z

Reserved: 2026-05-01T18:22:45.639Z

Link: CVE-2026-43617

cve-icon Vulnrichment

Updated: 2026-05-20T13:25:04.043Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-20T02:16:36.233

Modified: 2026-05-20T13:58:07.923

Link: CVE-2026-43617

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-20T10:38:37Z

Weaknesses