Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a 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. For example, something like: RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HApache HTTP Server
APPApache2.4.0 – 2.4.55
Related vulnerabilities
Apache HTTP Server mod_rewrite — ujawnienie kodu i RCE poprzez błędne escapowanie
Apache HTTP Server 2.4.50 — path traversal i RCE (niewystarczający patch CVE-2021-41773)
Apache HTTP Server 2.4.49 — path traversal i RCE (aktywnie exploitowany)
SSRF w mod_proxy Apache HTTP Server — przekierowanie żądań przez atakującego
Use-after-free w Apache HTTP Server z mod_ldap (CVE-2026-29167)