Puma is a web server for Ruby/Rack applications built for parallelism. Prior to version 6.4.2, puma exhibited incorrect behavior when parsing chunked transfer encoding bodies in a way that allowed HTTP request smuggling. Fixed versions limits the size of chunk extensions. Without this limit, an attacker could cause unbounded resource (CPU, network bandwidth) consumption. This vulnerability has been fixed in versions 6.4.2 and 5.6.8.
https://github.com/puma/puma/security/advisories/GHSA-c2f4-cvqm-65w2
https://github.com/puma/puma/security/advisories/GHSA-c2f4-cvqm-65w2
https://github.com/puma/puma/commit/5fc43d73b6ff193325e657a24ed76dec79133e93
https://github.com/puma/puma/commit/5fc43d73b6ff193325e657a24ed76dec79133e93