GHSA-P543-XPFM-54CP Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion)

Summary Rack::Multipart::Parser buffers the entire multipart preamble bytes before the first boundary in memory without any size limit. A client can send a large preamble followed by a valid boundary, causing significant memory use and potential process termination due to out-of-memory OOM...