Input validation error in Rsync - CVE-2026-53794

Vulnerability identifier: #VU142285

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53794

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in the max-alloc option handling when processing rsync protocol options from a remote peer. A remote attacker can send a max-alloc value of 0 to disable the per-allocation sanity cap and cause a denial of service.

An older or modified client can forward the zero value on the wire to an unpatched daemon, which honors it.

Rsync
Debian Linux
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing 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
Basesystem Module
openSUSE Leap
openEuler
Fedora
rsync-debugsource
rsync-debuginfo
rsync
rsync-help
rsync (Debian package)

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-debugsource - update to 3.2.7-12
rsync-help - 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

• https://github.com/RsyncProject/rsync/security/advisories/GHSA-p827-vwcp-m964

• Multiple vulnerabilities in Rsync
• SUSE update for rsync
• Fedora 44 update for rsync
• Fedora 43 update for rsync
• SUSE update for rsync
• openEuler 24.03 LTS SP3 update for rsync
• openEuler 24.03 LTS SP1 update for rsync
• openEuler 24.03 LTS SP4 update for rsync
• Debian update for rsync