The issue is related to the handling of HTTP/2 streams in the Apache HTTP Server. When a client resets an HTTP/2 stream using an RST frame, there is a time window where the request's memory resources are not immediately reclaimed. Instead, de-allocation is deferred until the connection is closed. A client can exploit this by sending new requests and resets, keeping the connection busy and open, and causing the memory footprint to grow. This can lead to a denial-of-service condition if the process runs out of memory before the connection is closed.