CVE-2026-58211: Linuxfoundation Nats-Server

Medium severity, CVSS 5.4. EPSS: 0.3% chance of exploitation in the next 30 days.

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured no_auth_user through a parser path used when the first client operation was not CONNECT, bypassing user-level connection restrictions such as allowed_connection_types or proxy_required that normal authentication would apply. This issue is fixed in versions 2.14.3 and 2.12.12.

Affected products

• Linuxfoundation Nats-Server: from 2.12.0, before 2.12.12 (fixed in 2.12.12); from 2.14.0, before 2.14.3 (fixed in 2.14.3)

Published 2026-07-08. Last modified 2026-07-09.