An attacker can send a flood of CONTINUATION frames, causing h2 to process them indefinitely. This results in an increase in CPU usage. Tokio task budget helps prevent this from a complete denial-of-service, as the server can still respond to legitimate requests, albeit with increased latency. More details at https://seanmonstar.com/blog/hyper-http2-continuation-flood/. Patches available for 0.4.x and 0.3.x versions.
An attacker with an HTTP/2 connection to an affected endpoint can send a steady stream of invalid frames to force the generation of reset frames on the victim endpoint. By closing their recv window, the attacker could then force these resets to be queued in an unbounded fashion, resulting in Out Of Memory (OOM) and high CPU usage. This fix is corrected in hyperium/h2#737, which limits the total number of …
Hyper is an HTTP library for Rust and h2 is an HTTP 2.0 client & server implementation for Rust. An issue was discovered in h2 v0.2.4 when processing header frames. It incorrectly processes the HTTP2 RST_STREAM frames by not always releasing the memory immediately upon receiving the reset frame, leading to stream stacking. As a result, the memory and CPU usage are high which can lead to a Denial of …