The upload module allows users to upload files and provides access checking for file downloads.
The module looks up files for download in the database and serves them for download after access checking. However, it does not account for the fact that certain database configurations will not consider case differences in file names. If a malicious user uploads a file which only differs in letter case, access will be granted for the earlier upload regardless of actual file access to that.
This issue affects Drupal 5.x and 6.x.
Vendor Status:
Drupal issued an update for this vulnerability