Authentication Bypass by Spoofing in Rsync - CVE-2026-53791

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Main Vulnerability Database Vulnerabilities #VU142288

Authentication Bypass by Spoofing in Rsync - CVE-2026-53791

Published: August 13, 2026


Vulnerability identifier: #VU142288
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-53791
CWE-ID: CWE-290
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to bypass host-based access control and spoof the daemon's source address.

The vulnerability exists due to authentication bypass by spoofing in PROXY-protocol mode when handling a direct client connection with a supplied PROXY header. A remote attacker can send a forged PROXY header to bypass host-based access control and spoof the daemon's source address.

The issue occurs when proxy protocol = true is enabled and the client connects directly rather than through a trusted proxy.


Affected software

Rsync
Debian Linux
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Basesystem Module
openSUSE Leap
openEuler
Fedora
rsync-debugsource
rsync-debuginfo
rsync
rsync-help
rsync (Debian package)
rsync (Red Hat package)

How to mitigate CVE-2026-53791

Install security update from vendor's website.

Rsync - update to 3.5.0
rsync-debugsource - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync-debuginfo - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync - addressed in versions 3.2.3-150400.3.34.1, 3.2.7-150600.3.24.1
rsync-help - update to 3.2.7-12
rsync-debugsource - update to 3.2.7-12
rsync-debuginfo - update to 3.2.7-12
rsync - update to 3.2.7-12
rsync (Debian package) - update to 3.5.0+ds1-0+deb13u1
rsync - addressed in versions 3.5.0-1.fc43, 3.5.0-1.fc44
rsync (Red Hat package) - update to 3.5.0-3.el10_2

External References

Related Security Bulletins