Cyber Resilience

CVE-2026-33523

Medium

Published: 04 May 2026

Published
04 May 2026
Modified
04 May 2026
KEV Added
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Patch
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CVSS Score v3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0033 56.3th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-33523 is a medium-severity DEPRECATED: HTTP response splitting (CWE-443) vulnerability in Apache Http Server. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 43.7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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.

CWE(s)
CWE-443NVD-CWE-Other

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Why these techniques?

HTTP response splitting in public-facing Apache server directly enables exploitation of the web application via crafted requests to untrusted backends.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

Affected Assets

apache
http server
2.4.0 — 2.4.67

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References