Vulnerabilities

RUSTSEC-2024-0003

Resource exhaustion vulnerability in h2 may lead to Denial of Service (DoS)

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
internal error resets emitted by default before the connection is closed.

RUSTSEC-2023-0034

Resource exhaustion vulnerability in h2 may lead to Denial of Service (DoS)

If an attacker is able to flood the network with pairs of HEADERS/RST_STREAM frames, such that the h2 application is not able to accept them faster than the bytes are received, the pending accept queue can grow in memory usage. Being able to do this consistently can result in excessive memory use, and eventually trigger Out Of Memory.

This flaw is corrected in hyperium/h2#668, which restricts remote reset stream count by default.

RUSTSEC-2024-0332

Degradation of service in h2 servers with CONTINUATION Flood

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.