CVE-2026-33523
Analyzed Analyzed - Analysis Complete
HTTP Response Splitting in Apache HTTP Server

Publication date: 2026-05-04

Last updated on: 2026-05-04

Assigner: Apache Software Foundation

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.
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Meta Information
Published
2026-05-04
Last Modified
2026-05-04
Generated
2026-06-16
AI Q&A
2026-05-05
EPSS Evaluated
2026-06-15
NVD
CVE-2026-33523
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
apache http_server From 2.4.0 (inc) to 2.4.67 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-443 This weakness can be found at CWE-113.
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Executive Summary

This vulnerability is an HTTP response splitting issue found in multiple Apache HTTP Server modules when used with untrusted or compromised backend servers.

It affects Apache HTTP Server versions up to 2.4.66 and allows attackers to manipulate HTTP responses by injecting malicious headers or content.

Users are advised to upgrade to version 2.4.67 to fix this vulnerability.

Impact Analysis

This vulnerability can allow attackers to perform HTTP response splitting attacks, which may lead to web cache poisoning, cross-site scripting (XSS), or other malicious activities.

The CVSS score of 6.5 indicates a medium severity with potential impacts on confidentiality and integrity, but no impact on availability.

Mitigation Strategies

Users are recommended to upgrade Apache HTTP Server to version 2.4.67, which fixes the HTTP response splitting vulnerability.

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