🛡️ CVE-2026-33216 — nats

🟠 CVSS 8.6 — High ✅ No Known Exploit CWE-256 NVD
8.6
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

NATS has MQTT plaintext password disclosure

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

For MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints.

Affected Versions

Any version before v2.12.6 or v2.11.15

Workarounds

Ensure monitoring end-points are adequately secured.

Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality high, integrity none, availability none.

Affected software

CVE-2026-33216 is recorded against 4 packages.

  • github.com/nats-io/nats-server
  • github.com/nats-io/nats-server/v2
  • nats
  • nats-server (from 2.12.0 up to 2.12.6)

Timeline and source

Published on 24 March 2026 and last revised on 27 March 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
advisories.nats.io (Web)
github.com (Package)

CVE-2026-33216 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 8.6
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
CWE CWE-256
Public Exploit ✅ No
Source NVD
Published 2026-03-24
Updated 2026-08-12
Modified 2026-03-27

Affected Packages

Software From version Fixed in
github.com/nats-io/nats-server — —
github.com/nats-io/nats-server/v2 — —
nats — —
nats-server 2.12.0 2.12.6

Similar Threats

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