CVE-2026-33523

Name: CVE-2026-33523
Creator: NVD / NIST
Published: 2026-05-04T15:16:04.227+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.44%

Last modified Jun 17, 2026

CVE-2026-33523 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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.. EPSS estimates a 0.44% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.44%

34.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-443

Affected Software

Vendor	Product	Versions
Apache	Http Server	>= 2.4.0, < 2.4.67

References

https://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
http://www.openwall.com/lists/oss-security/2026/05/04/23Mailing List, Third Party Advisory

Timeline

Published: May 4, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33523?

How severe is CVE-2026-33523?

CVE-2026-33523 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.44% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33523?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33523?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST