Don't Trust JWT Headers: Algorithm Confusion Attacks Explained
I keep encountering this JWT vulnerability in Python codebases, and it’s particularly concerning because it’s so easily overlooked. Developers implement what appears to be proper JWT authentication—they validate signatures, check expiration, handle all the edge cases. But there’s one subtle mistake that can completely undermine the entire security model. The issue is trusting the JWT’s own header to determine how to verify it. This is similar to asking someone to specify which method you should use to verify their identity. ...