NetSight
high8.8

CVE-2026-58253

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 2.14.0, 2.12.7, and 2.11.16, 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.

Affected products

VendorProductAffected versions
LinuxfoundationNats-Server
before 2.11.16
from 2.12.0 before 2.12.7

Weakness classification

References