Apollo Router's Compressed Payloads do not respect HTTP Payload Limits

The Apollo Router is a graph router written in Rust to run a federated supergraph that uses Apollo Federation. Versions 0.9.5 until 1.40.2 are subject to a Denial-of-Service (DoS) type vulnerability. When receiving compressed HTTP payloads, affected versions of the Router evaluate the limits.http_max_request_bytes configuration option after the entirety of the compressed payload is decompressed. If affected versions of the Router receive highly compressed payloads, this could result in significant memory consumption while the compressed payload is expanded. Router version 1.40.2 has a fix for the vulnerability. Those who are unable to upgrade may be able to implement mitigations at proxies or load balancers positioned in front of their Router fleet (e.g. Nginx, HAProxy, or cloud-native WAF services) by creating limits on HTTP body upload size.