CVE-2026-33247: NATS-Server sensitive information disclosure in monitoring endpoint

CVE-2026-33247 · Severity: high · CVSS 7.4 · Published 2026-03-25

NATS-Server is a high-performance messaging system used for cloud and edge computing. A security flaw allows sensitive login credentials to be exposed to anyone who can access the server's monitoring interface. If an attacker obtains these credentials, they could gain unauthorized access to the messaging network, potentially intercepting or tampering with business-critical data.

Technologies: github.com/nats-io/nats-server (Go), github.com/nats-io/nats-server/v2 (Go), Red Hat Multicluster Global Hub. Vendors: Go, Red Hat.

Quick answers

Is CVE-2026-33247 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33247 being exploited in the wild.
How severe is CVE-2026-33247?
High severity, with a CVSS score of 7.4, published 25 March 2026.
Which products and versions are affected?
github.com/nats-io/nats-server (Go) SEMVER:introduced=0; github.com/nats-io/nats-server/v2 (Go) SEMVER:introduced=0,fixed=2.11.15, SEMVER:introduced=0,fixed=2.11.15,introduced=2.12.0-RC.1,fixed=2.12.6; Red Hat Multicluster Global Hub 1.4.5, 1.5.4, 1.6.2.
Is there a fix for CVE-2026-33247?
Yes. github.com/nats-io/nats-server/v2 (Go): upgrade to 2.11.15, 2.12.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33247 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-33247?
Check whether you run github.com/nats-io/nats-server (Go), github.com/nats-io/nats-server/v2 (Go) or Red Hat Multicluster Global Hub at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/nats-io/nats-server/v2 (Go): upgrade to 2.11.15, 2.12.6 or later
    go get github.com/nats-io/nats-server/v2@v2.12.6

Technical details

NATS-Server is vulnerable to sensitive information disclosure when run with static credentials provided via command-line arguments (argv). The server's monitoring interface, specifically the `/debug/vars` endpoint, contains an unredacted copy of these arguments. An attacker with network access to the monitoring port can retrieve these credentials without authentication. This affects nats-server versions prior to 2.11.15 and 2.12.6. Remediation involves upgrading to patched versions or migrating credentials from command-line arguments to a secure configuration file.

Affected products

  • NATS.io nats-server < 2.11.15, >= 2.12.0-RC.1 < 2.12.6
  • Red Hat Multicluster Global Hub 1.4.5, 1.5.4, 1.6.2

Identifiers

  • CVE-2026-33247
  • GHSA-x6g4-f6q3-fqvv
  • GO-2026-4827

Timeline

  • 2026-03-24: advisory: NATS maintainers published security advisory 2026-14
  • 2026-03-25: disclosed: CVE-2026-33247 published to NVD
  • 2026-05-28: patched: Red Hat released security updates for Multicluster Global Hub

References

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