medium5.4
CVE-2026-58211
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system.
Impact
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
| Vendor | Product | Affected versions |
|---|---|---|
| Linuxfoundation | Nats-Server | from 2.12.0 before 2.12.12 from 2.14.0 before 2.14.3 |