Description

The MCP Server for WordPress WordPress plugin before 1.8.2 does not perform an ownership or sufficient capability check on its workflow create, update and delete REST routes, allowing users with the Contributor role to modify, delete and create site-wide workflow configuration, including workflows created by administrators.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "2.7",
  "pubDate": "2026-09-26T07:17:03.233Z",
  "pubdate": "2026-09-26T07:17:03.233Z",
  "executiveSummary": "The MCP Server for WordPress plugin contains a critical broken access control vulnerability originating from missing authorization checks within its REST API implementation. This flaw resides in the workflow creation, update, and deletion endpoints. Impacting all versions prior to 1.8.2, the vulnerability permits authenticated users possessing the 'Contributor' role to perform unauthorized administrative actions on site-wide workflow configurations. Because the plugin fails to validate ownership or sufficient administrative capabilities, a low-privileged contributor can manipulate, delete, or inject malicious workflows that were originally created by site administrators. This represents a significant security risk, as workflows often govern automated processes, content management, or data handling within the WordPress environment. The inability to enforce the principle of least privilege allows for potential unauthorized modifications to site logic, which could be leveraged to disrupt operations, gain persistent unauthorized access, or facilitate further compromise of the WordPress installation.",
  "technicalDetails": "The vulnerability manifests as an Insecure Direct Object Reference (IDOR) and broken access control issue within the REST API controller of the MCP Server for WordPress plugin. Specifically, the REST routes responsible for handling workflow lifecycle operations—create, update, and delete—lack the necessary capability validation logic required to restrict access to authorized administrators.\nRoot Cause Analysis: The plugin's server-side logic fails to invoke appropriate capability checks (e.g., current_user_can('manage_options')) before processing incoming requests to the workflow endpoints. By default, the REST API endpoints are exposed to any authenticated user without verifying if the requesting user possesses the privileges required to modify global site configurations.\nExploitation Method: An attacker authenticated as a Contributor can intercept or craft HTTP requests targeting the REST API endpoints associated with workflow management. Since the application does not enforce an ownership check or verify the user's role against the target workflow object, the API processes the unauthorized request as if it were legitimate. The attacker can modify existing workflows, delete critical automation, or create new workflows that execute within the context of the site, effectively overriding administrator-level settings.\nAttack Flow: 1. The attacker gains or holds a valid Contributor account. 2. The attacker identifies the REST API endpoint responsible for workflow modification through theme or plugin asset enumeration. 3. The attacker issues a POST, PUT, or DELETE request to the vulnerable endpoint. 4. The server receives the request, identifies the session as authenticated, but fails to check if the user has permission to manage workflows. 5. The application executes the requested operation on the global workflow state.\nImpact: Successful exploitation allows unauthorized users to modify site-wide workflow behavior. Depending on the plugin's functionality, this can lead to arbitrary code execution, bypass of security workflows, or data exfiltration if the workflows are capable of interacting with sensitive site data or external services. Because the workflows are global, the compromise is not limited to the attacker's own content, potentially affecting the entire site infrastructure."
}