CVE-2026-56154
Received Received - Intake

Use After Free in Apache HTTP Server mod_rewrite with Lookahead

Publication date: 2026-10-01

Last updated on: 2026-10-01

Assigner: Apache Software Foundation

Description
Use After Free vulnerability in Apache HTTP Server's mod_rewrite when using lookahead (%{LA-U:HTTP:...}) This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.

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Meta Information

Published
2026-10-01
Last Modified
2026-10-01
Generated
2026-10-01
AI Q&A
2026-10-01
EPSS Evaluated
N/A
NVD
CVE-2026-56154
EUVD
EUVD-2026-90894

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
apache http_server From 2.4.0 (inc) to 2.4.68 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

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Executive Summary

This is a Use After Free vulnerability in Apache HTTP Server's mod_rewrite module. It occurs when using lookahead directives like %{LA-U:HTTP:...}. The flaw allows an attacker to potentially execute arbitrary code or cause a denial of service by exploiting memory that has been freed but is still accessed.

Impact Analysis

If you use Apache HTTP Server with mod_rewrite and lookahead directives, this vulnerability could allow attackers to crash your server or run malicious code on your system. Servers running versions 2.4.0 through 2.4.68 are affected.

Mitigation Strategies

Upgrade Apache HTTP Server to a version beyond 2.4.68 to address the Use After Free vulnerability in mod_rewrite.

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