CVE-2023-25690
Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy
- Published
- Mar 7, 2023
- Updated
- Dec 18, 2025
- Assigning CNA
- apache
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HHigh · next 30 days
- Percentile
- 99.7%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
4CVE 2023 25690 Proof of concept - mod_proxy vulnerable configuration on Apache HTTP Server versions 2.4.0 - 2.4.55 leads to HTTP Request Smuggling vulnerability.
HTTP Request Smuggling lab: Apache 2.4.55 CRLF injection
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