rsync<3.5.0 TOCTOU in nondaemon receiver destdir handling
CVE-2026-53796 Published on August 13, 2026
rsync < 3.5.0 TOCTOU Race Condition via Destination Directory Handling
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.
Vulnerability Analysis
CVE-2026-53796 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Types
What is an insecure temporary file Vulnerability?
The software attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
CVE-2026-53796 has been classified to as an insecure temporary file vulnerability or weakness.
What is a TOCTTOU Vulnerability?
The software checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the software to perform invalid actions when the resource is in an unexpected state. This weakness can be security-relevant when an attacker can influence the state of the resource between check and use. This can happen with shared resources such as files, memory, or even variables in multithreaded programs.
CVE-2026-53796 has been classified to as a TOCTTOU vulnerability or weakness.
Products Associated with CVE-2026-53796
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Affected Versions
RsyncProject rsync:- Before and including 3.4.4 is affected.
- Version 3.5.0 is unaffected.