puma is a simple, fast, threaded, and highly concurrent HTTP 1.1 server for Ruby/Rack applications. Puma is intended for use in both development and production environments. It's great for highly concurrent Ruby implementations such as Rubinius and JRuby as well as as providing process worker support to support CRuby well.
Affected versions of this package are vulnerable to HTTP Request Smuggling. An attacker could smuggle an HTTP response, by using an invalid transfer-encoding header.
puma to version 3.12.5, 4.3.4 or higher.