Executive brief
MasterStudy LMS is a learning management system plugin for WordPress used to manage online courses and student registrations. The plugin fails to validate redirect URLs during user registration, allowing attackers to trick users into visiting malicious external websites by sending them trusted-looking links from the victim's site. This could enable phishing attacks that compromise student or instructor credentials.
Technical details
The vulnerability is an open redirect (CWE-601) in the user registration flow. The plugin accepts a redirect_page parameter in the registration AJAX endpoint (action=stm_lms_register) without validating that it points to a same-origin URL. An unauthenticated attacker can craft a registration request with an arbitrary external URL in the redirect_page field, which is then used to redirect the user after email confirmation. Prerequisites include: registration must be open, email confirmation (user pre-moderation) must be enabled, and the attacker needs the registration nonce (publicly disclosed in the registration form). When a victim clicks the confirmation link, they are redirected to the attacker's malicious site. The vulnerability was fixed in version 3.7.43.
Affected products
- MasterStudy LMS before 3.7.43
Timeline
- 2026-08-27: disclosed
- 2026-08-29: patched: Fixed in version 3.7.43