CVE-2024-33939 is an authentication bypass vulnerability classified under CWE-288 (Authentication Bypass Using an Alternate Path or Channel) affecting the Masteriyo - LMS (Learning Management System) product up to version 1.7.3. This vulnerability allows an unauthenticated attacker to access course progress information without proper authorization. The issue arises because the system fails to properly enforce authentication checks on certain alternate paths or channels, enabling unauthorized access to sensitive user data related to course progress. The vulnerability has a CVSS v3.1 base score of 5.3, indicating a medium severity level. The attack vector is network-based (AV:N), requires no privileges (PR:N), and no user interaction (UI:N), making it remotely exploitable by anyone with network access to the LMS. The impact is limited to confidentiality (C:L), with no impact on integrity or availability. No known exploits are currently reported in the wild, and no patches or fixes have been linked yet. The vulnerability was reserved in April 2024 and published in May 2025. Given the nature of LMS platforms, unauthorized access to course progress data could lead to privacy violations and potential leakage of user learning activities, which may be sensitive in academic or corporate training contexts.

For European organizations, especially educational institutions, corporate training providers, and e-learning platforms using Masteriyo - LMS, this vulnerability poses a risk to the confidentiality of learner data. Unauthorized access to course progress can undermine user privacy and trust, potentially violating GDPR requirements concerning personal data protection. While the vulnerability does not allow modification or disruption of services, the exposure of learning progress data could be exploited for social engineering or to gain insights into organizational training activities. This could be particularly sensitive in regulated sectors such as finance, healthcare, or government where training records may be linked to compliance. The medium severity score reflects a moderate risk; however, the ease of exploitation without authentication increases the urgency for mitigation. Organizations relying on Masteriyo - LMS should consider the reputational and regulatory implications of such data exposure.

Since no official patches are currently linked, European organizations should implement the following specific mitigations: 1) Restrict network access to the Masteriyo LMS instance by implementing IP whitelisting or VPN-only access to reduce exposure to untrusted networks. 2) Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting alternate paths or channels that could bypass authentication. 3) Conduct thorough access control audits and monitor LMS logs for unusual access patterns indicating potential exploitation attempts. 4) If possible, disable or restrict features related to course progress visibility until a patch is available. 5) Engage with the vendor or community to obtain updates or patches promptly and apply them as soon as released. 6) Educate LMS administrators and users about the risk and encourage vigilance for any anomalous behavior. 7) Consider deploying additional authentication layers or Single Sign-On (SSO) integrations that enforce stronger access controls beyond the vulnerable LMS component.