CVE-2024-21647 is a vulnerability in Puma HTTP server versions prior to 6.4.2 and 5.6.8 where improper parsing of chunked transfer encoding bodies allows unbounded resource consumption. This occurs because chunk extensions are not size-limited, enabling attackers to exhaust CPU and network bandwidth resources. The issue has been fixed in versions 6.4.2 and 5.6.8. No known workarounds exist.