Rails Active Storage has possible Path Traversal in DiskService

Impact

Active Storage's DiskService#path_for does not validate that the resolved filesystem path remains within the storage root directory. If a blob key containing path traversal sequences (e.g. ../) is used, it could allow reading, writing, or deleting arbitrary files on the server. Blob keys are expected to be trusted strings, but some applications could be passing user input as keys and would be affected.

Releases

The fixed releases are available at the normal locations.

Credit

This issue was responsibly reported by Hackerone researcher ksw9722.