In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.
Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to on.
Weakness
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Http_server | Apache | 2.4.26 (including) | 2.4.64 (excluding) |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-httpd-0:2.4.62-8.el8jbcs | * |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-mod_http2-0:2.0.29-5.el8jbcs | * |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-mod_jk-0:1.2.50-9.redhat_1.el8jbcs | * |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-mod_md-1:2.4.28-10.el8jbcs | * |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-mod_proxy_cluster-0:1.3.22-4.el8jbcs | * |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-mod_security-0:2.9.6-11.el8jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-httpd-0:2.4.62-8.el7jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_http2-0:2.0.29-5.el7jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_jk-0:1.2.50-9.redhat_1.el7jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_md-1:2.4.28-10.el7jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_proxy_cluster-0:1.3.22-4.el7jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_security-0:2.9.6-11.el7jbcs | * |
| Red Hat Enterprise Linux 10 | RedHat | mod_http2-0:2.0.29-2.el10_0.1 | * |
| Red Hat Enterprise Linux 8 | RedHat | httpd:2.4-8100020250728150834.489197e6 | * |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | RedHat | httpd:2.4-8020020250827160659.4cda2c84 | * |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | RedHat | httpd:2.4-8040020250827161824.522a0ee4 | * |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | RedHat | httpd:2.4-8040020250827161824.522a0ee4 | * |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | RedHat | httpd:2.4-8060020250827162806.ad008a3a | * |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | RedHat | httpd:2.4-8060020250827162806.ad008a3a | * |
| Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | RedHat | httpd:2.4-8060020250827162806.ad008a3a | * |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | RedHat | httpd:2.4-8080020250827163339.63b34585 | * |
| Red Hat Enterprise Linux 9 | RedHat | mod_http2-0:2.0.26-4.el9_6.1 | * |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | RedHat | mod_http2-0:1.15.19-3.el9_0.7 | * |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | RedHat | mod_http2-0:1.15.19-4.el9_2.7 | * |
| Red Hat Enterprise Linux 9.4 Extended Update Support | RedHat | mod_http2-0:2.0.26-2.el9_4.2 | * |
| Red Hat JBoss Core Services 2.4.62.SP1 | RedHat | * | |
| Apache2 | Ubuntu | devel | * |
| Apache2 | Ubuntu | esm-infra/bionic | * |
| Apache2 | Ubuntu | esm-infra/focal | * |
| Apache2 | Ubuntu | jammy | * |
| Apache2 | Ubuntu | noble | * |
| Apache2 | Ubuntu | plucky | * |
| Apache2 | Ubuntu | upstream | * |
Extended Description
While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.