---
id: CVE-2026-33216
title: >-
  NATS-Server is a High-Performance server for NATS.io, a cloud and edge native
  messaging system
summary: >-
  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, for MQTT deployments
  using usercodes/passwords: MQTT passwords are incorrectly classified as a
  non-auth…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N'
cwe:
  - CWE-256
  - CWE-213
vendor: linuxfoundation
product: nats-server
affected:
  - nats-server < 2.11.15
  - 'nats-server >= 2.12.0, < 2.12.6'
patched:
  - nats-server 2.12.6
published: '2026-03-25'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T13:19:22.887'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-33216'
references:
  - url: 'https://advisories.nats.io/CVE/secnote-2026-05.txt'
    label: security-advisories@github.com
  - url: >-
      https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099
    label: security-advisories@github.com
  - url: >-
      https://github.com/nats-io/nats-server/security/advisories/GHSA-v722-jcv5-w7mc
    label: security-advisories@github.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:21769'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:22347'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:23345'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-33216'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2451448'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33216.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-33216'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-33216'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-03-28T01:37:25.310195Z'
epss: 0.00631
epssPercentile: 0.47955
ingestedAt: '2026-07-20T12:38:40.669Z'
---

## Overview

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, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix. As a workaround, ensure monitoring end-points are adequately secured. Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.

## Affected

- `nats-server < 2.11.15`
- `nats-server >= 2.12.0, < 2.12.6`

## Remediation

Upgrade past the affected range:

- `nats-server 2.12.6`

## Vendor advisories

- **RHSA-2026:22347** · Red Hat · fixed in: Multicluster Global Hub 1.4.5 · released 2026-06-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:22347)
- **RHSA-2026:23345** · Red Hat · fixed in: Multicluster Global Hub 1.6.5 · released 2026-06-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:23345)
- **RHSA-2026:21769** · Red Hat · fixed in: Red Hat multicluster global hub 1.5.3 · released 2026-05-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:21769)