Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, previous bug fixes for symlink races in open() calls missed races …

Summary

Rsync is a file-copying tool that uses a delta-transfer algorithm to synchronize remote and local files. In versions prior to 3.4.3, previous bug fixes for symlink races in open() calls missed races in other path based system calls like chmod() and chown(). For rsync daemons with "use chroot = no" this allows an attacker with local filesystem access to change permissions, ownership or timestamp on a file outside the exported module. This issue is fixed in version 3.4.3.