If a WSGI server fails to sanitize newline characters in headers provided by the application, an attacker may inject additional HTTP headers or response splitting.
Rare but impactful flaws within underlying C modules (like unicodedata or ctypes ) used by networking libraries. Anatomy of the Exploit wsgiserver 02 cpython 3104 exploit
The most effective defense is to eliminate the vulnerable components entirely: If a WSGI server fails to sanitize newline
When a web server, such as a penetration testing lab machine or a live application, returns this specific header, it signals a combination of an outdated development server and an older Python version. returns this specific header