Time-of-check Time-of-use (TOCTOU) Race Condition in Rsync - CVE-2026-29518
Published: June 1, 2026
Vulnerability identifier: #VU133144
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-29518
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Samba
Affected software:
Rsync
Rsync
Detailed vulnerability description
The vulnerability allows a local user to disclose sensitive information and overwrite files outside the module.
The vulnerability exists due to a time-of-check time-of-use symlink race condition in daemon mode path handling when processing file operations on parent path components without chroot. A local user can replace a parent directory component with a symlink between the check and open operation to disclose sensitive information and overwrite files outside the module.
Only daemon configurations with use chroot = no for a module are vulnerable.
How to mitigate CVE-2026-29518
Install security update from vendor's website.