CVE-2026-33218: Linuxfoundation Nats-Server

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

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, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.

Affected products

• Linuxfoundation Nats-Server: before 2.11.15 (fixed in 2.11.15); from 2.12.0, before 2.12.6 (fixed in 2.12.6)

Published 2026-03-25. Last modified 2026-09-09.