VulnerabilityAnalyzed

CVE-2026-33223

An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header.

MEDIUM 5.4EPSS 0.21%

Does this matter?

Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1: 5.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS: 0.21% probability · 11th percentile
CISA KEV: Not listed
Weakness: CWE-290
Affected: linuxfoundation/nats-server
Source: security-advisories@github.com

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

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.