GO-2026-4533 nats-server websockets are vulnerable to pre-auth memory DoS in github.com/nats-io/nats-server

nats-server websockets are vulnerable to pre-auth memory DoS in github.com/nats-io/nats-server...

CVE-2026-27571

A flaw was found in nats-server. The WebSockets implementation fails to enforce a memory allocation limit during the decompression of WebSocket messages. A malicious compressed payload allows an attacker to cause an excessive memory consumption, eventually resulting in a server crash and a comple...

CVE-2026-27571 nats-server websockets are vulnerable to pre-auth memory DoS

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. Prior to versions 2.11.2 and 2.12.3, the implementation bound the memory size of a NATS...