Requests (aka python-requests) before 2.3.0 allows remote servers to obtain sensitive information by reading the Proxy-Authorization header in a redirected request.

Research is free — Hunters explains how the bug works, the root-cause code pattern, how the fix addresses it, and how to test whether a target is affected, in chat. Investigate & write exploit is a paid run — the engine reads the advisory and fix commits, then builds and validates a working proof-of-concept exploit with reproduction steps.