OpenProject is open-source, web-based project management software. Prior to version 17.3.0, a user with manage_agendas permission in any project can inject agenda items into meetings belonging to any other project on the instance, even projects they have no access to. No knowledge of the target project, meeting, or victim is required.

the attacker can blindly spray items into every meeting on the instance by iterating sequential section IDs. Version 17.3.0 patches the issue.