CVE-2026-43619: Time-of-check Time-of-use (TOCTOU) Race Condition in RsyncProject rsync
Rsync version 3.4.2 and prior contain symlink race condition vulnerabilities in path-based system calls including chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat that allow local attackers to redirect operations to files outside the exported rsync module. Attackers with local filesystem access can exploit the timing window between path resolution and syscall execution by swapping symlinks to apply sender-supplied permissions, ownership, timestamps, or filenames to arbitrary files outside the intended module boundary on rsync daemons configured with 'use chroot = no'.
AI Analysis
Technical Summary
CVE-2026-43619 is a TOCTOU race condition vulnerability affecting rsync versions up to 3.4.2. The vulnerability arises from symlink race conditions in system calls such as chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat. An attacker with local access can exploit the timing window between path resolution and syscall execution by swapping symlinks, thereby redirecting operations to arbitrary files outside the exported rsync module. This can lead to unauthorized modification of file permissions, ownership, timestamps, or filenames on rsync daemons configured without chroot isolation ('use chroot = no').
Potential Impact
Local attackers with filesystem access can exploit this vulnerability to apply sender-supplied file attributes or manipulate arbitrary files outside the intended rsync module boundary. This could result in unauthorized file modifications, potentially impacting system integrity. The vulnerability requires local access and specific rsync daemon configuration, limiting remote exploitation.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid running rsync daemons with 'use chroot = no' to reduce exposure. Restrict local filesystem access to trusted users and monitor configurations to prevent exploitation.
CVE-2026-43619: Time-of-check Time-of-use (TOCTOU) Race Condition in RsyncProject rsync
Description
Rsync version 3.4.2 and prior contain symlink race condition vulnerabilities in path-based system calls including chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat that allow local attackers to redirect operations to files outside the exported rsync module. Attackers with local filesystem access can exploit the timing window between path resolution and syscall execution by swapping symlinks to apply sender-supplied permissions, ownership, timestamps, or filenames to arbitrary files outside the intended module boundary on rsync daemons configured with 'use chroot = no'.
CVSS v4.0
Score 7.2high
Affected software
pkg:github/rsyncproject/rsyncRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-43619 is a TOCTOU race condition vulnerability affecting rsync versions up to 3.4.2. The vulnerability arises from symlink race conditions in system calls such as chmod, lchown, utimes, rename, unlink, mkdir, symlink, mknod, link, rmdir, and lstat. An attacker with local access can exploit the timing window between path resolution and syscall execution by swapping symlinks, thereby redirecting operations to arbitrary files outside the exported rsync module. This can lead to unauthorized modification of file permissions, ownership, timestamps, or filenames on rsync daemons configured without chroot isolation ('use chroot = no').
Potential Impact
Local attackers with filesystem access can exploit this vulnerability to apply sender-supplied file attributes or manipulate arbitrary files outside the intended rsync module boundary. This could result in unauthorized file modifications, potentially impacting system integrity. The vulnerability requires local access and specific rsync daemon configuration, limiting remote exploitation.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, avoid running rsync daemons with 'use chroot = no' to reduce exposure. Restrict local filesystem access to trusted users and monitor configurations to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-05-01T18:22:45.639Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a0d0f6cba1db473621796df
Added to database: 05/20/2026, 01:33:32 UTC
Last enriched: 07/15/2026, 10:32:20 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 82
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