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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.

PUBLISHED Reserved 2026-03-20 | Published 2026-05-04 | Updated 2026-05-04 | Assigner apache

Problem types

CWE-443: HTTP response splitting

Product status

Default status
unaffected

2.4.0 (semver)
affected

Timeline

2026-03-05:reported
2026-05-04:2.4.67 released
2026-05-04:fixed in 2.4.x by r1933360

Credits

Haruki Oyama (Waseda University) finder

Merih Mengisteab finder

Dawit Jeong finder

References

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

httpd.apache.org/security/vulnerabilities_24.html vendor-advisory

cve.org (CVE-2026-33523)

nvd.nist.gov (CVE-2026-33523)

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