CVE-2026-33217

Updated on 25 Mar 2026

Severity

7.1 High severity

Details

CVSS score
7.1
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Overview

About vulnerability

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 the $MQTT.> namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects.

Affected Versions

Any version before v2.12.6 or v2.11.15

Workarounds

None.

Details