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Improper Authentication

CVE-2026-58253

High
8.8/10

Summary

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.11.16, 2.12.x prior to 2.12.7, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.

  • LOW
  • ADJACENT_NETWORK
  • HIGH
  • CHANGED
  • NONE
  • NONE
  • LOW
  • LOW

CWE-287 - Improper Authentication

Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.

References

Advisory Timeline

  • Published