Improper Authentication Affecting nats package, versions <0.3.2-r0


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-NATS-15801752
  • published28 Mar 2026
  • disclosed25 Mar 2026

Introduced: 25 Mar 2026

NewCVE-2026-33248  (opens in a new tab)
CWE-287  (opens in a new tab)
CWE-295  (opens in a new tab)

How to fix?

Upgrade Chainguard nats to version 0.3.2-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nats package and not the nats package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

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 mTLS for client identity, with verify_and_map to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass. This does require a valid certificate from a CA already trusted for client certificates, and DN naming patterns which the NATS maintainers consider highly unlikely. So this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their DN construction patterns might conceivably be impacted. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, developers should review their CA issuing practices.

CVSS Base Scores

version 3.1