CVE-2026-33523

MEDIUM

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

Title source: cna

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.

References (2)

Core 2

Core References

Vendor Advisory vendor-advisory

https://httpd.apache.org/security/vulnerabilities_24.html

Mailing List, Third Party Advisory

http://www.openwall.com/lists/oss-security/2026/05/04/23

Scores

CVSS v3 6.5

EPSS 0.0026

EPSS Percentile 49.3%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-443

Status published

Products (2)

apache/http_server 2.4.0 - 2.4.67

Apache Software Foundation/Apache HTTP Server 2.4.0 - 2.4.66

Published May 04, 2026

Tracked Since May 04, 2026