CVE-2016-7038 in Moodle
Summary
by MITRE
In Moodle 2.x and 3.x, web service tokens are not invalidated when the user password is changed or forced to be changed.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability described in CVE-2016-7038 represents a critical security flaw in the Moodle learning management system affecting versions 2.x and 3.x. This issue stems from a fundamental mismanagement of authentication tokens within the web service architecture, creating a persistent security risk that undermines the integrity of user authentication mechanisms. The flaw specifically manifests when users undergo password changes or are forced to change their passwords through administrative intervention, leaving existing web service tokens valid and potentially exploitable by unauthorized parties.
The technical root cause of this vulnerability lies in the improper token lifecycle management within Moodle's web service implementation. When a user's password is modified through the standard authentication process or administrative forced password changes, the system fails to invalidate previously generated web service tokens that were created using the old password credentials. This creates a scenario where attackers who may have obtained legitimate web service tokens before a password change can continue to access restricted resources and perform privileged operations using those tokens. The flaw directly violates the principle of least privilege and authentication integrity, as the system does not properly enforce the revocation of access credentials when authentication credentials are modified.
From an operational impact perspective, this vulnerability significantly weakens the security posture of Moodle deployments across educational institutions and organizations relying on the platform. Attackers who gain access to valid web service tokens can maintain persistent access to user accounts and system resources even after password changes have been implemented, effectively bypassing the intended security controls. This creates a window of opportunity for unauthorized data access, modification, and potential lateral movement within the system. The vulnerability is particularly concerning in environments where web services are extensively used for integration with external applications, automated processes, or mobile access, as these tokens often carry elevated privileges and can be leveraged for more extensive attacks.
The security implications of this vulnerability align with several CWE classifications including CWE-613, which addresses insufficient session management, and CWE-306, which covers missing authentication. From an ATT&CK framework perspective, this weakness maps to techniques involving credential access and privilege escalation, specifically targeting the T1078 legitimate credentials and T1566 credential stuffing attack patterns. Organizations may find themselves vulnerable to attacks where compromised tokens remain functional despite password changes, potentially allowing attackers to maintain access to sensitive educational data, user information, and institutional resources. The vulnerability also increases the attack surface for social engineering and insider threat scenarios where malicious actors might exploit this weakness to maintain unauthorized access.
Mitigation strategies for CVE-2016-7038 should focus on immediate patching of affected Moodle installations to the latest available versions that contain the necessary fixes for proper token invalidation. Organizations should implement comprehensive token management policies that include automatic invalidation of web service tokens during password change events, regular token rotation schedules, and monitoring for suspicious token usage patterns. Security teams should conduct thorough audits of existing web service tokens and invalidate any that were generated before recent password changes. Additionally, implementing multi-factor authentication mechanisms and least privilege access controls can help reduce the impact of this vulnerability by limiting the damage that can be accomplished even with valid but potentially compromised tokens. The remediation process should also include user education regarding the importance of immediate password changes and the risks associated with token exposure.