Executive brief
The AI Engine WordPress plugin allows unauthenticated visitors to execute arbitrary AI queries against the site owner's configured AI provider (e.g., OpenAI) account by bypassing authorization checks on an admin-only feature. An attacker can obtain a guest token and use it to run AI requests with custom instructions and model selection, causing unauthorized charges to the site owner's provider account and potentially exposing sensitive AI capabilities to malicious use.
Technical details
The vulnerability is an authorization bypass (CWE-862) in the AI Engine WordPress plugin versions before 3.7.2. The plugin's editor assistant feature accepts REST API requests but fails to verify that the caller has administrator privileges, instead relying solely on a REST nonce token that the plugin freely distributes to anonymous visitors via a public session route. An attacker first calls POST /wp-json/mwai/v1/start_session to obtain a valid restNonce, then uses it to execute arbitrary AI queries by POSTing to /wp-json/mwai-ui/v1/editor/submit with attacker-controlled parameters (system prompt, model, environment ID). The request executes against the site owner's configured provider account and API key, incurring unauthorized charges. The fix, released in version 3.7.2, implements a permission callback (can_use_assistant()) that returns HTTP 401 for unauthenticated callers and strips server parameters before chatbot resolution.
Affected products
- AI Engine Contributors AI Engine 3.4.0 to 3.7.1
Timeline
- 2026-08-24: disclosed
- 2026-08-24: patched: Fixed in version 3.7.2