The Secure Meeting (Pulse Collaboration) in Pulse Connect Secure (formerly Juniper Junos Pulse) before 7.1R22.1, 7.4, 8.0 before 8.0R11, and 8.1 before 8.1R3 provides different messages for attempts to join a meeting depending on the status of the meeting, which allows remote attackers to enumerate valid meeting ids via a series of requests.