The Sensei LMS WordPress plugin before 4.26.4 contains a broken access control vulnerability in the legacy save_new_message handler hooked on the init action, which validates only a generic nonce without verifying course enrollment or restricting post_id to valid post types. Authenticated attackers, including unprivileged Subscribers, can supply an arbitrary post_id for any course, lesson, or quiz to create a private message addressed to that post's author, bypassing the enrollment checks enforced by the newer REST send-message controller.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
automattic:sensei lms