Wsgiserver 02 Cpython 3104 Exploit May 2026

Stay paranoid, patch regularly, and never trust user input—even the HTTP grammar itself can be an attack vector. This article is for educational and defensive purposes only. No actual exploit code is provided. If you believe you’ve discovered a vulnerability in a WSGI server, follow responsible disclosure practices.

Migrate immediately from any self‑named wsgiserver to cheroot , waitress , or gunicorn . Update to the latest Python 3.10 patch (e.g., 3.10.15+), or better, move to Python 3.11/3.12 with modern security features. wsgiserver 02 cpython 3104 exploit

Normalize paths using os.path.abspath or urllib.parse.unquote and check that the final path is within the intended directory. 4. Memory Corruption via Malformed Headers CPython 3.10.4 has hardened memory management, but C extensions used by certain WSGI servers (e.g., uWSGI’s C core) have had buffer overflows in the past. A specially crafted HTTP header with an overly long value might trigger undefined behavior. Stay paranoid, patch regularly, and never trust user

Sending a request with both Content-Length and Transfer-Encoding: chunked in a specific order could cause the older wsgiserver to treat the message differently than a reverse proxy. If you believe you’ve discovered a vulnerability in

Use a well-maintained WSGI server (e.g., Waitress v2.1+, Gunicorn v20.1+). Avoid custom or legacy versions of wsgiserver . 2. CRLF Injection in Headers 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.