CVE-2026-93563 Io.netty/netty-codec-smtp: netty: unbounded multi-line response accumulation in smtpresponsedecoder leads to memory-exhaustion dos

A flaw was found in Netty's SmtpResponseDecoder component. A remote attacker, acting as a malicious or man-in-the-middle MITM SMTP server, could exploit this by sending a specially crafted, unbounded multi-line SMTP response without a terminator. This vulnerability leads to unbounded memory...