PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.get_signing_key_from_jwt / verify_signature=False)

Summary PyJWKClient.getsigningkeyfromjwttoken — the first step of the JWKS verification flow documented in docs/usage.rst — must decode a token's payload before its signature can be checked, via jwt.apijwt.decodecompletetoken, options="verifysignature": False. That call parses the payload with...