CVE-2026-29518 Rsync < 3.4.3 TOCTOU Race Condition Allows Symlink-Based Arbitrary File Write

What is CVE-2026-29518?

CVE-2026-29518 is a high-severity vulnerability in RsyncProject rsync, published on 20 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false.

Weakness: CWE-367

Which versions are affected by CVE-2026-29518?

It affects 1 product.

Products include Samba Rsync.

How do I fix CVE-2026-29518?

Upgrade to a fixed version.

Is CVE-2026-29518 being exploited?

There is no known exploitation of CVE-2026-29518 in the wild and no public exploit code.

Other vulnerabilities in RsyncProject rsync

• CVE-2017-15994 Security feature bypass in n/a Critical 9.8
• CVE-2026-53791 rsync < 3.5.0 Daemon IP Spoofing via PROXY Protocol Header Critical 9.1
• CVE-2026-70461 rsync 3.2.5 < 3.5.0 Heap Out-of-Bounds Write via files-from Entry High 8.8
• CVE-2026-70455 rsync 3.4.2 < 3.5.0 DoS via --zt Zstandard Compression Thread Exhaustion High 8.7
• CVE-2026-70463 rsync 3.1.0 < 3.5.0 Authorization Bypass via auth users Directive Parsing High 8.6

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2026-29518, AZL-87012, BELL-CVE-2026-29518, CLSA-2026-1779694338, CLSA-2026-1779694460, CLSA-2026-1779694727 and 12 more.