Description

Casdoor through 4.4.0 contains an authorization bypass vulnerability in the /api/mcp endpoint that allows attackers with any application's clientId and clientSecret to gain unrestricted access to user administration across all organizations. Attackers can enumerate user records including password salts and email addresses, create administrator accounts, modify existing users, and delete them in any organization by supplying legitimate credentials from a single application.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.9",
  "pubDate": "2026-09-15T12:17:55.407Z",
  "pubdate": "2026-09-15T12:17:55.407Z",
  "executiveSummary": "Casdoor versions through 4.4.0 are affected by a critical authorization bypass vulnerability located within the /api/mcp endpoint. This vulnerability allows an attacker possessing a valid clientId and clientSecret from any registered application to circumvent identity-based access controls.\nBy successfully authenticating as a standard application, an attacker can escalate privileges to perform administrative actions across all organizations within the Casdoor instance. This unauthorized access grants the ability to enumerate sensitive user information, including password salts and email addresses, as well as perform unauthorized account lifecycle management, such as the creation of rogue administrator accounts, user modification, and account deletion.\nThe vulnerability represents a significant security risk, as it effectively nullifies organizational isolation and authorization boundaries. Any authenticated application entity can become a vector for global administrative compromise, leading to total system takeover. The exploit does not require specialized infrastructure, only legitimate application credentials which are standard in a Casdoor deployment environment.\nOrganizations relying on Casdoor for centralized identity and access management should prioritize immediate remediation to prevent widespread data exposure and persistent administrative backdoors.",
  "technicalDetails": "The vulnerability exists in the /api/mcp endpoint within Casdoor, which fails to properly validate the authorization scope of the provided application credentials. While the endpoint is intended for Model Context Protocol (MCP) interactions or management, it lacks the necessary server-side logic to verify if the requesting entity (identified by clientId and clientSecret) holds the appropriate permissions to access or modify user records across organizations.\nThe root cause is a broken access control mechanism where the system treats any application successfully identified via its credentials as a trusted administrative actor for the entire platform. The application logic fails to implement the principle of least privilege, allowing the API handler to process global user administrative requests regardless of the origin application's scoped access levels.\nThe exploitation flow is straightforward: 1) The attacker obtains a legitimate clientId and clientSecret for any application currently managed within the Casdoor instance. 2) The attacker crafts an HTTP request targeting the /api/mcp endpoint. 3) The request includes the credentials in the authentication headers or payload. 4) Because the server fails to cross-reference the application's scope with the requested administrative action, the API processes the command. 5) The attacker issues commands to query the underlying database for user records, including password salts, or executes write operations to create or modify user objects.\nThe impact of this exploit is severe, as it facilitates full-scale administrative control. By creating an administrator account via the /api/mcp interface, an attacker can establish persistent access to the Casdoor management console, bypassing organizational silos. The exposure of password salts presents a risk of offline dictionary or brute-force attacks against user credentials, further escalating the impact beyond the immediate Casdoor instance. Furthermore, the ability to delete or modify users across all organizations compromises the integrity of the entire identity provider (IdP).\nAffected systems include all Casdoor installations up to and including version 4.4.0. The vulnerability is network-exposed as the /api/mcp endpoint is generally accessible to any application capable of reaching the Casdoor instance. Successful exploitation requires no elevated platform privileges initially, as the system trusts the credentials provided by any valid application."
}