Apache 2.4.55 mod_proxy HTTP Request Smuggling

Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow for an HTTP request smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution.

apache attack data http http request smuggling http server non request request smuggling rewriterule server smuggling target url