CVE-2026-33216
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.
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version



Related Resources
References
https://github.com/nats-io/nats-server/security/advisories/GHSA-v722-jcv5-w7mc, https://nvd.nist.gov/vuln/detail/CVE-2026-33216, https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099, https://advisories.nats.io/CVE/secnote-2026-05.txt, https://github.com/nats-io/nats-server
