CVE-2026-33523

Apache HTTP Server: multiple modules: HTTP response splitting forwarding malicious status line

State: Published
Severity: 6.5 Medium
Published: May 4, 2026
Updated: May 4, 2026
Reserved: Mar 20, 2026

Description

HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers.

This issue affects Apache HTTP Server: from through 2.4.66.

Users are recommended to upgrade to version 2.4.67, which fixes the issue.

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N	CISA-ADP

Weaknesses

CWE-443 HTTP response splitting

Affected Products

Product	Versions
Apache HTTP ServerApache Software Foundation	2.4.0 through 2.4.66Affected

References

https://httpd.apache.org/security/vulnerabilities_24.htmlvendor-advisory
http://www.openwall.com/lists/oss-security/2026/05/04/23

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