What is CVE-2026-33246?

CVE-2026-33246 is a medium-severity vulnerability in Nats-io Nats-server, classified under Improper Authentication. CVSS score: 6.4/10. Published 2026-03-25.

How severe is CVE-2026-33246?

Medium severity. CVSS v3 base score is 6.4 out of 10.

Auth bypass in Nats-io Nats-server

CVE-2026-33246

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. This is supposed to provide enough informa…

Vulnerability class: Broken Authentication

EPSS: 0.000 (10.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N.

Affected products

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

Weakness classification (CWE)

References

https://github.com/nats-io/nats-server/security/advisories/GHSA-55h8-8g96-x4hj (x_refsource_CONFIRM)
https://advisories.nats.io/CVE/secnote-2026-08.txt (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-33246?: CVE-2026-33246 is a medium-severity vulnerability in Nats-io Nats-server, classified under Improper Authentication. CVSS score: 6.4/10. Published 2026-03-25.
How severe is CVE-2026-33246?: Medium severity. CVSS v3 base score is 6.4 out of 10.