Executive brief
rclone, a popular command-line tool for managing files on cloud storage, is vulnerable to a path traversal flaw when using certain non-default local encoding settings. An attacker who can control file names on a source storage system (like Amazon S3) could craft malicious names that, when synchronized or copied by a victim, cause rclone to create or overwrite files outside of the intended destination folder. This could lead to the corruption of important system files or unauthorized modification of data with the permissions of the user running rclone.
Technical details
The vulnerability exists in the local backend's path resolution logic. When a local destination is configured with an encoding that omits 'Dot' (e.g., --local-encoding Raw), rclone's internal fullwidth character representation for relative path components (．．) is decoded back into literal '..' components. The `backend/local.localPath` function then joins this decoded string with the destination root using `filepath.Join`, which resolves the traversal and escapes the root. On Windows, a similar bypass occurs if 'BackSlash' is omitted from the encoding mask. The root cause is a lack of post-conversion path validation (such as a `filepath.Rel` check) to ensure the final native path remains within the configured destination. The issue is patched in version 1.75.0.
Affected products
- rclone rclone v1.51.0 - v1.74.4
Timeline
- 2026-07-31: advisory: GitHub Advisory GHSA-7p4m-qxvv-g567 published
- 2026-08-05: patched: Version 1.75.0 released