CVE-2026-33223

Name: CVE-2026-33223
Creator: NVD / NIST
Published: 2026-03-25T21:16:47.397+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.4/10EPSS 0.21%

Last modified Jun 17, 2026

CVE-2026-33223 is a medium-severity vulnerability rated 5.4/10 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, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. EPSS estimates a 0.21% 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, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Metrics

CVSS 3.1

5.4/10

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

EPSS Probability

0.21%

11.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-290

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-2026-09.txtVendor Advisory
https://github.com/nats-io/nats-server/security/advisories/GHSA-pwx7-fx9r-hr4hVendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2026-33223?

How severe is CVE-2026-33223?

CVE-2026-33223 has a CVSS score of 5.4/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33223?

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-2026-33223?

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

Scan your code now

Source: NVD / NIST