Input validation error in Rsync - CVE-2026-53794
Published: August 13, 2026
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
Vulnerability details
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.
Affected software
Rsync
How to mitigate CVE-2026-53794
Install security update from vendor's website.
Rsync - update to 3.5.0