Time-of-check Time-of-use (TOCTOU) Affecting rsync-daemon package, versions <0:3.5.1-1.amzn2023.0.1


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.13% (3rd percentile)

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  • Snyk IDSNYK-AMZN2023-RSYNCDAEMON-20247754
  • published29 Sept 2026
  • disclosed13 Aug 2026

Introduced: 13 Aug 2026

CVE-2026-53796  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 rsync-daemon to version 0:3.5.1-1.amzn2023.0.1 or higher.
This issue was patched in ALAS2023-2026-3131.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rsync-daemon package and not the rsync-daemon package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

rsync before 3.5.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability in the non-daemon receiver's destination directory handling that allows an attacker who can manipulate destination path parent components to redirect file writes to unintended locations. Attackers can substitute a symlink for a component of the destination path between the path resolution and chdir() call, causing the receiver's working directory to be established outside the intended destination tree so that subsequent relative-path file writes land in unintended filesystem locations.

CVSS Base Scores

version 3.1