User Impersonation Affecting github.com/nats-io/nats-server/v2/server package, versions <2.11.15>=2.12.0-RC.1 <2.12.6


Severity

Recommended
0.0
medium
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.21% (12th percentile)

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  • Snyk IDSNYK-GOLANG-GITHUBCOMNATSIONATSSERVERV2SERVER-15763399
  • published25 Mar 2026
  • disclosed24 Mar 2026
  • creditUnknown

Introduced: 24 Mar 2026

CVE-2026-33223  (opens in a new tab)
CWE-290  (opens in a new tab)

How to fix?

Upgrade github.com/nats-io/nats-server/v2/server to version 2.11.15, 2.12.6 or higher.

Overview

github.com/nats-io/nats-server/v2/server is an A simple, secure and performant communications system for digital systems, services and devices.

Affected versions of this package are vulnerable to User Impersonation via incomplete removal of the Nats-Request-Info header. An attacker can impersonate another user or service by injecting a crafted header into messages, potentially misleading systems that rely on this header for identity verification.

CVSS Base Scores

version 4.0
version 3.1