CVE-2026-33621: PinchTab: Unapplied Rate Limiting Middleware Allows Unbounded Brute-Force of API Token

PinchTab v0.7.7 through v0.8.4 contain incomplete request-throttling protections for auth-checkable endpoints. In v0.7.7 through v0.8.3, a fully implemented RateLimitMiddleware existed in internal/handlers/middleware.go but was not inserted into the production HTTP handler chain, so requests were not subject to the intended per-IP throttle.

In the same pre-v0.8.4 range, the original limiter also keyed clients using X-Forwarded-For, which would have allowed client-controlled header spoofing if the middleware had been enabled. v0.8.4 addressed those two issues by wiring the limiter into the live handler chain and switching the key to the immediate peer IP, but it still exempted /health and /metrics from rate limiting even though /health remained an auth-checkable endpoint when a token was configured.

This issue weakens defense in depth for deployments where an attacker can reach the API, especially if a weak human-chosen token is used. It is not a direct authentication bypass or token disclosure issue by itself. PinchTab is documented as local-first by default and uses 127.0.0.1 plus a generated random token in the recommended setup.

PinchTab’s default deployment model is a local-first, user-controlled environment between the user and their agents; wider exposure is an intentional operator choice. This lowers practical risk in the default configuration, even though it does not by itself change the intrinsic base characteristics of the bug.

This was fully addressed in v0.8.5 by applying RateLimitMiddleware in the production handler chain, deriving the client address from the immediate peer IP instead of trusting forwarded headers by default, and removing the /health and /metrics exemption so auth-checkable endpoints are throttled as well.