LimeSurvey Community Edition 7.7.0 contains a stored cross-site scripting vulnerability in the Central Participants Database blocklist control. An authenticated user with only global participantpanel:import permission can import a CSV participant_id containing HTML. The import flow persists that value without model validation. When a CPDB editor opens the participant list, LimeSurvey derives ButtonGroupWidget id and name attributes from participant_id and inserts them without HTML encoding, causing attacker-controlled markup to execute in the victim's authenticated LimeSurvey origin. Exploitation can access session-exposed data and issue same-origin requests with the victim's effective permissions.