What is CVE-2023-25690?

CVE-2023-25690 is a critical-severity vulnerability in Apache HTTP Server, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2023-03-07.

How severe is CVE-2023-25690?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2023-25690 known to be exploited?

58 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apache HTTP Server

CVE-2023-25690

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.

Vulnerability class: HTTP Request Smuggling

Published 2023-03-07 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.845 (99.7th percentile), scored 2026-10-16.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.845 · newest: 0.845 · change: 0.000

Affected products

Apache HTTP Server
Apache Software Foundation HTTP Server — versions 2.4.0

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2023-25690?: CVE-2023-25690 is a critical-severity vulnerability in Apache HTTP Server, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2023-03-07.
How severe is CVE-2023-25690?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2023-25690 known to be exploited?: 58 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.