Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to version 22.4.0rc1, the Twisted Web HTTP 1.1 server, located in the `twisted.web.http` module, parsed several HTTP request constructs more leniently than permitted by RFC 7230. This non-conformant parsing can lead to desync if requests pass through multiple HTTP parsers, potentially resulting in HTTP request smuggling. Users who may be affected use Twisted Web's HTTP 1.1 server and/or proxy and also pass requests through a different HTTP server and/or proxy. The Twisted Web client is not affected. The HTTP 2.0 server uses a different parser, so it is not affected. The issue has been addressed in Twisted 22.4.0rc1. Two workarounds are available: Ensure any vulnerabilities in upstream proxies have been addressed, such as by upgrading them; or filter malformed requests by other means, such as configuration of an upstream proxy. #### Bugs * <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1009030> #### Notes Author| Note ---|--- [rayveldkamp](<https://launchpad.net/~rayveldkamp>) | For focal and earlier, patch requires backporting major changes to how HTTP packets are buffered and processed which is intrusive and could have high risk of regression.

Affected Package

OS OS Version Package Name Package Version
ubuntu 22.04 twisted 22.1.0-2ubuntu2.3
ubuntu upstream twisted 22.4.0-1
ubuntu upstream twisted 22.4.0-1
ubuntu 14.04 twisted any
ubuntu upstream twisted 22.4.0
ubuntu 16.04 twisted any