OpenProject is an open-source, web-based project management software. Prior to version 16.6.2, a low‑privileged logged-in user can view the full names of other users. Since user IDs are assigned sequentially and predictably (e.g., 1 to 1000), an attacker can extract a complete list of all users’ full names by iterating through these URLs. The same behavior can also be reproduced via the OpenProject API, allowing automated retrieval of full names through the API as well. This issue has been patched in version 16.6.2. Those who are unable to upgrade may apply the patch manually.