CVE-2026-43617CWE-289

Rsync < 3.4.3 Authorization Bypass via Hostname Resolution

Medium · published May 20, 2026

CVSS v4.0
6.3
EPSS
0%
Percentile
23.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.3 · MEDIUM
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
EPSS
0.00315 · 23.2th percentile
Weakness
CWE-289 · Authentication Bypass by Alternate Name
Published
2026-05-20T00:52Z
EPSS history
Timeline
  • 20 MAY 00:52Z
    Rsync < 3.4.3 Authorization Bypass via Hostname Resolution
    cvelistv5