PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. PinchTab v0.7.8 through v0.8.3 accepted the API token from a token URL query parameter in addition to the Authorization header. When a valid API credential is sent in the URL, it can be exposed through request URIs recorded by intermediaries or client-side tooling, such as reverse proxy access logs, browser history, shell history, clipboard history, and tracing systems that capture full URLs.

This issue is an unsafe credential transport pattern rather than a direct authentication bypass. It only affects deployments where a token is configured and a client actually uses the query-parameter form. PinchTab's security guidance already recommended Authorization: Bearer <token>, but v0.8.3 still accepted ?token= and included first-party flows that generated and consumed URLs containing the token.

This was addressed in v0.8.4 by removing query-string token authentication and requiring safer header-or session-based authentication flows.