CVE-2025-67848 is an authentication bypass vulnerability identified in the Moodle learning management system (LMS), specifically impacting versions 4.1.0, 4.4.0, 4.5.0, 5.0.0, and 5.1.0. The vulnerability stems from improper handling of user suspension status within the Learning Tools Interoperability (LTI) Provider authentication mechanism. Normally, suspended users should be prevented from authenticating and accessing the system; however, the LTI authentication handlers fail to enforce this restriction. This flaw allows suspended users to bypass authentication controls and gain unauthorized access to Moodle instances. The vulnerability is exploitable remotely over the network without requiring user interaction, though it requires the attacker to have at least low privileges (PR:L). The impact includes potential unauthorized disclosure of sensitive educational data and the ability to perform unauthorized actions within the Moodle environment. The CVSS v3.1 score is 8.1, reflecting high severity due to the high confidentiality and integrity impacts and ease of exploitation. Although no known exploits are currently reported in the wild, the widespread use of Moodle in educational institutions globally increases the risk of exploitation once public exploit code becomes available. The vulnerability highlights a critical weakness in the LTI authentication flow, which is widely used for integrating external learning tools and services, making it a significant concern for organizations relying on Moodle for secure user management and access control.

For European organizations, particularly educational institutions, universities, and corporate training providers using Moodle, this vulnerability poses a significant risk. Unauthorized access by suspended users could lead to exposure of confidential student data, intellectual property, exam materials, and personal information, violating GDPR and other data protection regulations. The integrity of course content and user records could be compromised, potentially enabling malicious modifications or fraudulent activities. The availability impact is low, but the breach of confidentiality and integrity can damage organizational reputation and lead to regulatory penalties. Given Moodle's popularity in Europe, exploitation could disrupt educational operations and erode trust in digital learning platforms. The vulnerability also raises concerns about the security of integrated third-party learning tools via LTI, which may be indirectly affected by unauthorized access.

Organizations should prioritize updating Moodle installations to patched versions once available from the Moodle security team. Until patches are released, administrators should audit and restrict LTI Provider configurations, disabling or limiting LTI authentication for suspended users where possible. Implement additional access controls and monitoring around LTI authentication events to detect anomalous login attempts by suspended accounts. Review and tighten user suspension policies and ensure suspension status is consistently enforced across all authentication mechanisms. Employ network segmentation and firewall rules to limit access to Moodle instances to trusted networks and users. Conduct regular security assessments and penetration testing focused on authentication flows and third-party integrations. Educate administrators and users about the risks of unauthorized access and encourage prompt reporting of suspicious activities. Finally, maintain comprehensive logging and alerting to facilitate rapid incident response if exploitation is suspected.