CVE-2026-23918

Red Hat statement

This issue marked as Important rather than Moderate because it involves a memory safety violation (double free) in the HTTP/2 request handling path, which is directly exposed to untrusted network input. A double free condition can corrupt the heap allocator’s internal metadata, enabling attackers to manipulate memory layout and potentially achieve arbitrary code execution (RCE) under favorable conditions. In this case, the flaw is triggered during an early stream reset in HTTP/2, meaning it can be exercised pre-authentication by a remote client without requiring complex application-level interaction. Given that Apache HTTP Server is widely deployed in internet-facing environments, even a low-probability RCE path significantly elevates risk.

Red Hat mitigation

To mitigate this issue, disable the `mod_http2` module in your Apache HTTP Server configuration. This can be achieved by commenting out or removing the `LoadModule http2_module modules/mod_http2.so` line in the Apache configuration file (e.g., `/etc/httpd/conf.modules.d/00-base.conf` or a similar configuration file). After modifying the configuration, restart the httpd service for the changes to take effect. This action will impact services relying on HTTP/2 functionality.