An issue was discovered in hyper v0.13.7. h2-0.2.4 Stream stacking occurs when the H2 component processes HTTP2 RSTSTREAM frames. As a result the memory and CPU usage are high which can lead to a Denial of Service (DoS).

Hyperium Hyper before 0.14.19 does not allow for customization of the maxheaderlistsize method in the H2 third-party software, allowing attackers to perform HTTP2 attacks.

hyper is an HTTP library for Rust. In versions prior to 0.14.10, hyper's HTTP server and client code had a flaw that could trigger an integer overflow when decoding chunk sizes that are too big. This allows possible data loss, or if combined with an upstream HTTP proxy that allows chunk sizes larger than hyper does, can result in "request smuggling" or "desync attacks." The vulnerability is patched in version 0.14.10. Two possible workarounds exist. One may reject requests manually that contain a Transfer-Encoding header or ensure any upstream proxy rejects Transfer-Encoding chunk sizes greater than what fits in 64-bit unsigned integers.