CVE-2026-33217

Name: CVE-2026-33217
Creator: NVD / NIST
Published: 2026-03-25T20:16:32.473+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.19%

Last modified Jun 17, 2026

CVE-2026-33217 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

Description

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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.19%

8.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-863

Affected Software

Vendor	Product	Versions
Linuxfoundation	Nats-Server	< 2.11.15
Linuxfoundation	Nats-Server	>= 2.12.0, < 2.12.6

References

https://advisories.nats.io/CVE/secnote-2026-07.txtVendor Advisory
https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5Vendor Advisory

Timeline

Published: Mar 25, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33217?

How severe is CVE-2026-33217?

CVE-2026-33217 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33217?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33217?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST