CVE-2019-9518

Some HTTP/2 implementations are vulnerable to a flood of empty frames,
potentially leading to a denial of service. The attacker sends a stream of
frames with an empty payload and without the end-of-stream flag. These
frames can be DATA, HEADERS, CONTINUATION and/or PUSH_PROMISE. The peer
spends time processing each frame disproportionate to attack bandwidth.
This can consume excess CPU.