Vulnerability · Published Oct 1, 2026 · Assigned by apache

CVE-2026-56154Apache HTTP Server: mod_rewrite use-after-free via %{LA-U:HTTP:...}

Critical 9.8

In plain English

A critical-severity use-after-free in Apache HTTP Server from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 54.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10httpd2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8httpd2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9httpd2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10httpd-core2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:9httpd-core2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10httpd-devel2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8httpd-devel2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9httpd-devel2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10httpd-filesystem2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8httpd-filesystem2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9httpd-filesystem2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10httpd-manual2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8httpd-manual2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9httpd-manual2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10httpd-tools2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8httpd-tools2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9httpd-tools2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:8mod_http21.15.7-10.module_el8.10.0+4233+8b7d9181.7ALSA-2026:92616
AlmaLinux:8mod_http21.15.7-10.module_el8.10.0+4270+e5f13fdb.7ALSA-2026:92616
AlmaLinux:10mod_ldap2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8mod_ldap2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9mod_ldap2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10mod_lua2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:9mod_lua2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:8mod_md1:2.0.8-8.module_el8.10.0+4295+280de5aa.4ALSA-2026:92616
AlmaLinux:10mod_proxy_html1:2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8mod_proxy_html1:2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9mod_proxy_html1:2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10mod_session2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8mod_session2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9mod_session2.4.62-13.el9_8.9ALSA-2026:88229
AlmaLinux:10mod_ssl1:2.4.63-13.el10_2.8ALSA-2026:89860
AlmaLinux:8mod_ssl1:2.4.37-65.module_el8.10.0+4332+2bef2e0d.13ALSA-2026:92616
AlmaLinux:9mod_ssl1:2.4.62-13.el9_8.9ALSA-2026:88229
Alpine:v3.21apache22.4.69-r0ALPINE-CVE-2026-56154
Alpine:v3.22apache22.4.69-r0ALPINE-CVE-2026-56154
Alpine:v3.23apache22.4.69-r0ALPINE-CVE-2026-56154
Alpine:v3.24apache22.4.69-r0ALPINE-CVE-2026-56154
Debian:12apache2no fix listedDEBIAN-CVE-2026-56154
Debian:13apache22.4.69-1~deb13u1DEBIAN-CVE-2026-56154
Debian:14apache22.4.69-1DEBIAN-CVE-2026-56154
Rocky Linux:10httpd0:2.4.63-13.el10_2.8RLSA-2026:89860
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+1830+22f0c9e0RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40197+0231e209.8RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+1842+4a9649e8.2RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+1938+3b7755d4.3RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40206+be2c8a50.8RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40257+286895ef.9RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+1984+1bed3124.4RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40312+2c72bb9b.10RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+2061+8d03fdec.5RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40402+af9563a3.13RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40045+6ce8579b.6RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+40053+5a18018e.7RLSA-2026:92616
Rocky Linux:8httpd0:2.4.37-65.module+el8.10.0+1840+b070a976.1RLSA-2026:92616
Rocky Linux:9httpd0:2.4.62-13.el9_8.9RLSA-2026:88229
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+40257+286895ef.7RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+40204+716978aa.6RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+40197+0231e209.5RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+2061+8d03fdec.4RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+1938+3b7755d4.3RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+1883+38ed6c58.1RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+1830+22f0c9e0RLSA-2026:92616
Rocky Linux:8mod_http20:1.15.7-10.module+el8.10.0+1775+6b057638RLSA-2026:92616
Rocky Linux:8mod_md1:2.0.8-8.module+el8.10.0+40053+5a18018e.2RLSA-2026:92616
Rocky Linux:8mod_md1:2.0.8-8.module+el8.9.0+1370+89cc8ad5RLSA-2026:92616
Rocky Linux:8mod_md1:2.0.8-8.module+el8.10.0+40369+03c444c1.4RLSA-2026:92616
Ubuntu:22.04:LTSapache22.4.52-1ubuntu4.24USN-8898-1
Ubuntu:22.04:LTSapache22.4.52-1ubuntu4.24UBUNTU-CVE-2026-56154
Ubuntu:24.04:LTSapache22.4.58-1ubuntu8.16USN-8898-1
Ubuntu:24.04:LTSapache22.4.58-1ubuntu8.16UBUNTU-CVE-2026-56154
Ubuntu:26.04:LTSapache22.4.66-2ubuntu2.5UBUNTU-CVE-2026-56154
Ubuntu:26.04:LTSapache22.4.66-2ubuntu2.5USN-8898-1
Ubuntu:26.10apache2no fix listedUBUNTU-CVE-2026-56154

Affected products (as reported)

VendorProductVersions
Apache Software Foundation Apache HTTP Server 2.4.0 – through 2.4.68

Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References