What is CVE-2026-33216?

CVE-2026-33216 is a high-severity vulnerability in Nats-io Nats-server, classified under Plaintext Storage of a Password. CVSS score: 8.6/10. Published 2026-03-25.

How severe is CVE-2026-33216?

High severity. CVSS v3 base score is 8.6 out of 10.

Vulnerability in Nats-io Nats-server

CVE-2026-33216

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-authen…

EPSS: 0.001 (15.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.

Affected products

Nats-io Nats-server — versions < 2.11.15, >= 2.12.0-RC.1, < 2.12.6

Weakness classification (CWE)

CWE-256 — Plaintext Storage of a Password

References

https://github.com/nats-io/nats-server/security/advisories/GHSA-v722-jcv5-w7mc (x_refsource_CONFIRM)
https://github.com/nats-io/nats-server/commit/b5b63cfc35a57075e09c1f57503d31721bed8099 (x_refsource_MISC)
https://advisories.nats.io/CVE/secnote-2026-05.txt (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33216?: CVE-2026-33216 is a high-severity vulnerability in Nats-io Nats-server, classified under Plaintext Storage of a Password. CVSS score: 8.6/10. Published 2026-03-25.
How severe is CVE-2026-33216?: High severity. CVSS v3 base score is 8.6 out of 10.