Netty is a network application framework for development of protocol servers and clients. Prior to 4.2.16.Final, Netty's Http3FrameCodec buffers incoming data for HTTP/3 reserved frame types up to the wire-specified payload length without limits; decodeFrame trusts payLoadLength, allowing an attacker to open multiple QUIC streams and send reserved frames with very large payload lengths to cause memory exhaustion and denial of service. This issue is fixed in version 4.2.16.Final.