CVE-2026-102587 in Moodle
Summary
by MITRE • 09/30/2026
A flaw was found in Moodle. User list filters do not properly enforce visibility restrictions on user profile fields. An authorized user with manager privileges can filter user lists using profile attributes they are not permitted to view directly, resulting in unauthorized information disclosure by inferring hidden user data.
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in the Learning Management System Moodle represents a significant authorization bypass that allows for the enumeration of sensitive user data through indirect means. This flaw specifically targets the functionality responsible for filtering and searching within the global or course-specific user lists, which are administrative interfaces typically restricted to users with elevated privileges such as managers or teachers. While direct access to individual user profile fields is governed by strict visibility rules based on role-based access control policies, the search mechanism fails to apply these same restrictions when processing filter criteria. This architectural inconsistency creates a side-channel through which an attacker can bypass intended privacy controls and infer information that should remain hidden from their current permission level.
From a technical perspective, the root cause lies in how the backend query logic handles user profile fields during list filtering operations. When a manager attempts to search for users based on specific profile attributes, such as department, location, or custom text fields, the system executes database queries that do not adequately check whether the requesting user has explicit permission to view those particular field values. Instead of returning only data accessible to the requester's role, the filter logic may return matches where the hidden attribute meets the search criteria, even if the actual value is masked in standard views. This allows an authorized but unauthorized-to-view actor to perform a form of blind inference or boolean-based enumeration. By systematically testing different values for these restricted fields and observing whether specific users appear in the filtered results, an attacker can reconstruct sensitive details about other users without ever directly accessing their profile pages.
The operational impact of this vulnerability is primarily centered on information disclosure and privacy violation within educational institutions that rely on Moodle to manage student, staff, and faculty data. Unauthorized access to personal identifiable information such as home addresses, phone numbers, or internal organizational hierarchies can lead to severe consequences including targeted phishing attacks, social engineering campaigns, and potential physical safety risks for individuals whose private details are exposed. Furthermore, this flaw undermines the trust model of the platform by demonstrating that administrative privileges do not strictly equate to unrestricted data access as intended by privacy configurations. It also poses compliance risks for institutions subject to regulations like FERPA in the United States or GDPR in Europe, where unauthorized disclosure of student and employee records can result in legal penalties and reputational damage.
This vulnerability aligns with CWE-284 Improper Access Control, specifically illustrating a failure to enforce proper authorization checks during data retrieval operations that involve filtering mechanisms. It also maps closely to the MITRE ATT&CK technique T1078 Valid Accounts, as it leverages legitimate administrative credentials to access restricted information through an unintended pathway rather than exploiting a software bug in authentication or encryption. The attack vector is classified under Privilege Escalation via Indirect Means because the user does not gain higher system privileges but achieves unauthorized data visibility by abusing the logic of search functions.
To mitigate this risk, administrators must ensure that their Moodle instance is updated to the latest stable version where patches for authorization checks in user list filters have been applied. If immediate patching is not feasible, a temporary workaround involves restricting access to the user management and filtering interfaces entirely to super-administrators who require broad data visibility, while limiting manager-level users to viewing only basic profile information that does not include sensitive custom fields. Additionally, implementing strict logging and monitoring for unusual search patterns or high-volume queries against restricted attributes can help detect potential exploitation attempts in real-time. Regular audits of role capabilities should also be conducted to ensure that the principle of least privilege is strictly enforced across all administrative functions within the learning management system.