What is CVE-2026-56154?

CVE-2026-56154 is a critical-severity vulnerability in Apache Software Foundation HTTP Server, classified under Use After Free. CVSS score: 9.8/10. Published 2026-10-01.

How severe is CVE-2026-56154?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Use After Free in Apache Software Foundation HTTP Server

CVE-2026-56154

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.

Vulnerability class: Use-After-Free

Published 2026-10-01 · last modified 2026-10-01.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Apache Software Foundation HTTP Server

Weakness classification (CWE)

CWE-416 — Use After Free

References

httpd.apache.org/security/vulnerabilities_24.html (vendor-advisory)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2026-56154?: CVE-2026-56154 is a critical-severity vulnerability in Apache Software Foundation HTTP Server, classified under Use After Free. CVSS score: 9.8/10. Published 2026-10-01.
How severe is CVE-2026-56154?: Critical severity. CVSS v3 base score is 9.8 out of 10.