CVE-2022-24801: 
Python vulnerability analysis and mitigation

The vulnerability CVE-2022-24801 affects the Twisted Web HTTP 1.1 server, specifically in the twisted.web.http module, prior to version 22.4.0rc1. The vulnerability was discovered and disclosed in April 2022, where the server was found to parse several HTTP request constructs more leniently than permitted by RFC 7230. This affected the core HTTP parsing functionality in Twisted, an event-based framework for internet applications supporting Python 3.6+ (GitHub Advisory).

The vulnerability stems from multiple non-conformant HTTP parsing issues: Content-Length header values could have + or - prefixes, illegal characters were permitted in chunked extensions (including LF character), chunk lengths in hexadecimal format could have a 0x prefix, and HTTP headers were stripped of all leading and trailing ASCII whitespace instead of only space and HTAB characters. The vulnerability has been assigned a CVSS v3.1 base score of 8.1 HIGH with vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H (NVD).

The non-conformant parsing can lead to request desync when requests pass through multiple HTTP parsers, potentially resulting in HTTP request smuggling. This is particularly concerning for systems that use Twisted Web's HTTP 1.1 server or proxy in combination with different HTTP servers or proxies. The vulnerability could allow attackers to bypass request validation or access control mechanisms implemented at the proxy level (GitHub Advisory).

The primary mitigation is to upgrade to Twisted version 22.4.0rc1 or later, which addresses the vulnerability. For systems that cannot immediately upgrade, two alternative workarounds are available: ensure any vulnerabilities in upstream proxies have been addressed through updates, or filter malformed requests using other means, such as configuring an upstream proxy. The HTTP 2.0 server and Twisted Web client are not affected by this vulnerability (GitHub Advisory).