---
id: CVE-2026-56154
title: >-
  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.
summary: >-
  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.
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: apache
product: http_server
affected:
  - 'http_server >= 2.4.0, < 2.4.69'
patched:
  - http_server 2.4.69
published: '2026-10-01'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T13:33:38.377'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56154'
references:
  - url: 'https://httpd.apache.org/security/vulnerabilities_24.html'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/10/01/17'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56154.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-56154'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2544869'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-56154'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56154'
  - url: 'https://access.redhat.com/errata/RHSA-2026:74858'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00536
epssPercentile: 0.44999
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-01T19:05:26.006334Z'
ingestedAt: '2026-10-01T18:55:42.362Z'
---

## Overview

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.

## Affected

- `http_server >= 2.4.0, < 2.4.69`

## Remediation

Upgrade past the affected range:

- `http_server 2.4.69`

## Vendor advisories

- **RHSA-2026:74858** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-10-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:74858)
- **Red Hat VEX** · Important · affected: Red Hat JBoss Core Services, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat JBoss Core Services · updated 2026-10-10 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56154.json)