What is CVE-2026-33215?

CVE-2026-33215 is a medium-severity vulnerability in Linuxfoundation Nats-server, classified under Improper Authentication. CVSS score: 6.5/10. Published 2026-03-24.

How severe is CVE-2026-33215?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Linuxfoundation Nats-server

CVE-2026-33215

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client…

Vulnerability class: Broken Authentication

EPSS: 0.002 (15.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L.

Affected products

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

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
security-advisories@github.com (x_refsource_MISC, Broken Link)

Frequently asked questions

What is CVE-2026-33215?: CVE-2026-33215 is a medium-severity vulnerability in Linuxfoundation Nats-server, classified under Improper Authentication. CVSS score: 6.5/10. Published 2026-03-24.
How severe is CVE-2026-33215?: Medium severity. CVSS v3 base score is 6.5 out of 10.