CVE-2026-33523 Details
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.
A vulnerability allowing HTTP response splitting has been identified in multiple Apache HTTP Server modules. This issue arises when the server interacts with untrusted or compromised backend servers, and it can be exploited to manipulate the response headers sent to the client, potentially leading to HTTP desynchronization attacks. The vulnerability affects Apache HTTP Server versions 2.4.0 prior to 2.4.66.
Users are advised to upgrade to Apache HTTP Server version 2.4.67, which addresses this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 4, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| http://www.openwall.com/lists/oss-security/2026/05/04/23 | CVE | Mailing ListThird Party Advisory |
| https://httpd.apache.org/security/vulnerabilities_24.html | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| NVD-CWE-Other | Weakness Not in a Standard CWE Category | [email protected] |
| CWE-443 | DEPRECATED: HTTP response splitting | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| apache http server | >= 2.4.0, < 2.4.67 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| May 4, 2026 | Initial Analysis | [email protected] |
| May 4, 2026 | CVE Modified | CVE |
| May 4, 2026 | CVE Modified | CISA-ADP |
| May 4, 2026 | New CVE Received | [email protected] |