CVE-2026-33217

Updated on 25 Mar 2026

Severity

6.5 Medium severity

Details

CVSS score
6.5
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Overview

About vulnerability

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 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Details

Affected packages:
github.com/nats-io/nats-server @ 2.1.4 (+39 more)
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 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.