Local file modification via symlink races
Published May 20, 2026 · Updated May 20, 2026
TOCTOU races in Rsync Project rsync 3.4.2 and earlier allow local users to modify files outside an exported daemon module. Path-based calls in set_file_attrs(), finish_transfer(), and related receiver code resolve paths before acting, so swapped symlinks redirect sender-supplied modes, ownership, timestamps, names, or file operations. Exploitation requires local filesystem access to a writable module on a daemon configured with use chroot = no; the bounded consequence is unauthorized modification outside the module.
Summary
What happened
TOCTOU races in Rsync Project rsync 3.4.2 and earlier allow local users to modify files outside an exported daemon module. Path-based calls in set_file_attrs(), finish_transfer(), and related receiver code resolve paths before acting, so swapped symlinks redirect sender-supplied modes, ownership, timestamps, names, or file operations. Exploitation requires local filesystem access to a writable module on a daemon configured with use chroot = no; the bounded consequence is unauthorized modification outside the module.
The record
- CVE
- CVE-2026-43619
- Published
- May 20, 2026
- Updated
- May 20, 2026
- Vendor
- Rsync Project
- Product
- rsync
- Classifications
- CWE-863, CWE-367, CWE-59, T1070.006, T1222.002
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 20, 2026CVE publishedPublication date reported by the CVE source.
- May 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <3.4.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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