CVE-2021-4399 in Edwiser Bridge Plugin
Summary
by MITRE • 07/01/2023
The Edwiser Bridge plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including,2.0.6. This is due to missing or incorrect nonce validation on the user_data_synchronization_initiater(), course_synchronization_initiater(), users_link_to_moodle_synchronization(), connection_test_initiater(), admin_menus(), and subscribe_handler() function. This makes it possible for unauthenticated attackers to perform unauthorized actions via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 04/10/2026
The edwiser bridge plugin for wordpress represents a critical security vulnerability classified as cross-site request forgery within versions up to and including 206. this vulnerability stems from insufficient or absent nonce validation mechanisms within multiple core functions of the plugin's codebase. the affected functions include user_data_synchronization_initiater course_synchronization_initiater users_link_to_moodle_synchronization connection_test_initiater admin_menus and subscribe_handler all of which fail to properly verify the authenticity of incoming requests through cryptographic nonce tokens. the absence of proper nonce validation creates a fundamental weakness that allows malicious actors to craft forged requests that appear legitimate to the wordpress application. this vulnerability operates under the common weakness enumeration framework as cwe 352 which specifically addresses cross-site request forgery flaws in web applications. the attack vector requires social engineering techniques where an attacker must convince a privileged site administrator to click on a malicious link or visit a compromised website that triggers the forged request. when executed successfully this vulnerability enables unauthenticated attackers to perform unauthorized actions on behalf of administrators with full privileges. the operational impact extends beyond simple privilege escalation as it can lead to complete compromise of the wordpress installation through unauthorized modifications to user data synchronization settings course synchronization parameters user linking operations connection testing procedures administrative menu configurations and subscription handling mechanisms. the attack model aligns with the mitre attack framework under the privilege escalation and persistence tactics where adversaries can establish long-term access to the wordpress environment through compromised administrative sessions. the vulnerability affects the core functionality of the edwiser bridge plugin which serves as a bridge between wordpress and moodle learning management systems, making it particularly dangerous for educational institutions and organizations relying on integrated learning platforms. organizations running affected versions face significant risk of data manipulation unauthorized user creation, course content alteration, and potential full system compromise. the exploitation requires minimal technical skill from attackers since it leverages existing administrative trust relationships and does not require direct access to the system. proper nonce implementation would require each state-changing request to include a unique cryptographic token generated server-side and validated upon receipt. this validation ensures that requests originate from legitimate sources within the authenticated session rather than from external malicious actors. the vulnerability highlights the critical importance of implementing proper request validation mechanisms in wordpress plugins and demonstrates how seemingly minor oversights in security implementation can lead to severe operational consequences. organizations should immediately upgrade to patched versions of the edwiser bridge plugin and implement additional monitoring for suspicious administrative activities. the recommended mitigation strategy includes not only updating the plugin but also reviewing all administrative user sessions and implementing additional security layers such as two-factor authentication and regular security audits to prevent exploitation of similar vulnerabilities in other components of the wordpress ecosystem.