BIT-NATS-2026-33217 NATS allows MQTT clients to bypass ACL checks

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using ACLs on message subjects, these ACLs were not applied in the $MQTT. namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions...

GHSA-JXXM-27VP-C3M5 NATS allows MQTT clients to bypass ACL checks

Background NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. The nats-server provides an MQTT client interface. Problem Description When using ACLs on message subjects, these ACLs were not applied in t...