A path traversal vulnerability exists in rsync. It stems from behavior enabled by the `--inc-recursive` option, a default-enabled option for many client options and can be enabled by the server even if not explicitly enabled by the client. When using the `--inc-recursive` option, a lack of proper symlink verification coupled with deduplication checks occurring on a per-file-list basis could allow a server to write files outside of the client's intended destination directory. A malicious server could write malicious files to arbitrary locations named after valid directories/paths on the client.
Workaround:
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '.../...//' (doubled triple dot slash) sequences that can resolve to a location that is outside of that directory.