CVE-2026-58213 NATS Server: MQTT SUBSCRIBE Protocol Injection via Leaf Node/Route Forwarding allows arbitrary NATS command injection

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.1 and 2.12.9, an MQTT client could include protocol control characters in subscription filters that were later forwarded as NATS protocol data to route or leafnode connections, corrupti...

CVE-2026-58213

NATS Server (nats-server) before versions 2.14.1 and 2.12.9 is vulnerable: an MQTT client can include protocol control characters in subscription filters, which are later forwarded as NATS protocol data to route or leafnode connections. This corrupts the forwarded protocol stream and allows injec...