How to detect HTTP/2 abuse in Apache web server logs

Apache HTTP Server, a widely used web server, faces vulnerabilities in its mod_http2 module, notably CVE-2026-23918, a double-free vulnerability that can lead to remote code execution if exploited, especially for servers not using Apache's MPM prefork. This vulnerability, along with others like CVE-2023-44487 and CVE-2023-45802, exploits the HTTP/2 feature RST_STREAM, which allows multiple requests in a single TCP connection, making detection more complex than with HTTP/1.1. To counteract these threats, configuring Apache to use debug logging is advised for capturing stream-level activities, which is crucial for forensic analysis but too verbose for regular use. Tools like Datadog can assist in monitoring these potential exploits by providing insights into server activity, allowing operators to detect signs of abuse such as latency spikes, high-volume stream resets, and worker process crashes, and to apply appropriate measures such as blocking IPs or updating server patches.