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.
Published: 2026-10-01
Score: 9.8 Critical
EPSS: n/a
KEV: No
Impact: Potential Memory Corruption or Denial of Service via use‑after‑free
Action: Patch Upgrade
AI Analysis

Impact

Apache HTTP Server’s mod_rewrite module contains a use‑after‑free condition that is triggered when a request includes a look‑ahead expression of the form %{LA-U:HTTP:...}. The freed memory can be reclaimed and subsequently accessed, allowing an attacker to corrupt memory. This memory corruption can result in a crash or denial of service. No evidence in the CVE description indicates that the flaw can be used for arbitrary code execution.

Affected Systems

Apache Software Foundation’s Apache HTTP Server versions 2.4.0 through 2.4.68 are affected.

Risk and Exploitability

The vulnerability can be invoked via HTTP traffic, making it reachable from the network. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog, which does not diminish the risk posed by a known use‑after‑free flaw. Attackers can send crafted URLs that activate mod_rewrite logic, potentially triggering memory corruption. The potential impact includes crash or denial of service, making the risk high. The CVSS score of 9.8 marks this as a Critical vulnerability.

Generated by OpenCVE AI on October 1, 2026 at 22:06 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade Apache HTTP Server to version 2.4.69 or later to apply the fix delivered by the Apache Software Foundation.
  • Restart the Apache HTTP Server to apply the update.
  • If an upgrade is not immediately possible, consider disabling the mod_rewrite module or restricting its use to trusted URLs only to mitigate the risk of exploitation.

Generated by OpenCVE AI on October 1, 2026 at 22:06 UTC.

Tracking

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Advisories

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History

Thu, 01 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
References

Thu, 01 Oct 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Thu, 01 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
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.
Title Apache HTTP Server: mod_rewrite use-after-free via %{LA-U:HTTP:...}
Weaknesses CWE-416
References

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-10-01T20:09:23.709Z

Reserved: 2026-06-19T12:42:54.699Z

Link: CVE-2026-56154

cve-icon Vulnrichment

Updated: 2026-10-01T20:09:23.709Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-01T17:17:26.610

Modified: 2026-10-01T21:17:22.267

Link: CVE-2026-56154

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T22:15:13Z

Weaknesses