What happened
The WordPress AI Engine plugin's MCP OAuth Dynamic Client Registration endpoint is missing authorization, allowing unauthenticated registration against the MCP OAuth service.
Why it matters
AI Engine adds an MCP server surface to WordPress. An unauthenticated, under-authorized OAuth registration endpoint lets an attacker inject or consume MCP clients/credentials against a site's AI chatbot and connected tools.
Attack vector
The MCP module's OAuth 2.1 Dynamic Client Registration endpoint is registered without proper authorization, so an unauthenticated caller can register/consume MCP clients or abuse the registration flow on the WordPress site.
Affected systems
AI Engine – The Chatbot, AI Framework & MCP for WordPress up to and including 3.8.6.
Mitigation
Update to the AI Engine version that authorizes the /wp-json/mcp/v1/oauth/register endpoint; if not yet fixed, disable the MCP OAuth module.