CVE-2025-6639 is an authorization bypass vulnerability classified under CWE-285, found in the Tutor LMS Pro plugin for WordPress, a widely used eLearning and online course management solution. The vulnerability arises from an Insecure Direct Object Reference (IDOR) in the tutor_assignment_submit() function, which handles viewing and editing of assignment submissions. Specifically, the plugin fails to validate a user-controlled key parameter properly, allowing authenticated users with minimal privileges (Subscriber-level or higher) to access and modify assignment submissions belonging to other students. This lack of proper authorization checks means that an attacker can bypass intended access controls, compromising the confidentiality and integrity of student assignment data. The vulnerability affects all versions up to and including 3.8.3. The CVSS v3.1 base score is 5.4 (medium severity), reflecting that the attack vector is network-based, requires low privileges, no user interaction, and impacts confidentiality and integrity but not availability. No patches or known exploits are currently reported, but the flaw represents a significant risk in educational environments where data privacy and integrity are critical. The vulnerability underscores the need for secure coding practices around access control and input validation in multi-tenant web applications, especially those handling sensitive academic data.

The primary impact of CVE-2025-6639 is unauthorized disclosure and modification of student assignment submissions within affected Tutor LMS Pro installations. This compromises the confidentiality and integrity of academic records, potentially leading to privacy violations, academic dishonesty, and loss of trust in the eLearning platform. Educational institutions and organizations relying on Tutor LMS Pro for course delivery could face reputational damage, regulatory compliance issues (especially under data protection laws like GDPR), and operational disruptions if sensitive student data is manipulated or leaked. Since the vulnerability can be exploited by users with minimal privileges, insider threats or compromised low-level accounts pose a significant risk. Although availability is not affected, the breach of data integrity could undermine the validity of assessments and certifications issued through the platform. The medium severity rating reflects the moderate ease of exploitation combined with the sensitive nature of the data involved. Organizations worldwide using this plugin in their WordPress environments are at risk until the vulnerability is remediated.

To mitigate CVE-2025-6639, organizations should immediately audit their Tutor LMS Pro plugin versions and upgrade to a patched release once available from the vendor. In the absence of an official patch, administrators should implement strict role-based access controls to limit Subscriber-level users from accessing assignment submission functions. Custom code or WordPress hooks can be used to enforce additional authorization checks on the tutor_assignment_submit() function, validating that users can only view or edit their own submissions. Monitoring and logging access to assignment data should be enhanced to detect suspicious activity indicative of exploitation attempts. Additionally, organizations should conduct user privilege reviews to minimize the number of users with elevated access rights. Employing Web Application Firewalls (WAFs) with rules targeting suspicious parameter manipulation may provide temporary protection. Finally, educating users about the risks of sharing credentials and enforcing strong authentication mechanisms can reduce the likelihood of account compromise leading to exploitation.