CVE-2025-3647 identifies an incorrect authorization vulnerability in Moodle, an open-source learning management system widely used by educational institutions globally. The vulnerability affects Moodle versions 4.1.0, 4.3.0, 4.4.0, and 4.5.0. The core issue is that the system lacks sufficient authorization checks when users attempt to access cohort data, which is typically used to group users for course enrollment and management. Due to this flaw, users with limited privileges can retrieve cohort information they are not authorized to see, potentially exposing sensitive user grouping data. The vulnerability requires the attacker to have some level of privileges (PR:L) but does not require user interaction (UI:N) and can be exploited remotely over the network (AV:N). The impact is limited to confidentiality (C:L) without affecting integrity or availability. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N, resulting in a score of 4.3, indicating medium severity. No public exploits or active exploitation have been reported. The vulnerability was published on April 25, 2025, and is recognized by CISA. The lack of patch links suggests that fixes may be pending or available through Moodle's official updates. Organizations relying on Moodle for user management and course delivery should prioritize verifying access controls around cohort data and apply patches once available.

The primary impact of CVE-2025-3647 is unauthorized disclosure of cohort data within Moodle installations. Cohort data often contains sensitive information about user groupings, which can reveal organizational structures, enrollment details, or user roles. Exposure of this data can lead to privacy violations, targeted social engineering, or unauthorized insight into institutional operations. While the vulnerability does not allow modification or disruption of services, the confidentiality breach can undermine trust in the LMS and potentially violate data protection regulations such as GDPR or FERPA. Educational institutions, training providers, and organizations using Moodle for internal training are at risk. The medium severity score reflects that exploitation requires some privileges but no user interaction, making it moderately accessible to insiders or compromised accounts. The absence of known exploits reduces immediate risk but does not eliminate the potential for future attacks. Organizations worldwide using affected Moodle versions should consider this a moderate threat to data confidentiality.

1. Apply official Moodle security updates as soon as they are released that address CVE-2025-3647. Monitor Moodle security advisories regularly. 2. In the interim, review and tighten access control policies related to cohort data, ensuring that only authorized roles can query or retrieve cohort information. 3. Implement role-based access control (RBAC) audits to verify that user privileges align strictly with job functions. 4. Restrict network access to Moodle administrative interfaces and APIs to trusted IP ranges where feasible. 5. Enable detailed logging and monitoring of cohort data access to detect unusual or unauthorized queries. 6. Educate administrators and privileged users about the risk of unauthorized data access and encourage prompt reporting of suspicious activity. 7. Consider deploying web application firewalls (WAFs) with custom rules to detect anomalous access patterns targeting cohort endpoints. 8. Conduct periodic security assessments and penetration tests focusing on authorization controls within Moodle deployments. These steps go beyond generic patching advice by emphasizing access control audits, monitoring, and network restrictions tailored to the specific vulnerability context.