CVE-2026-33218

Description

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 packages (6)

• Bitnami/natsfrom 0, < 2.11.15, >= 2.12.0, < 2.12.6
• Debian/nats-serverfrom 0
• Go/github.com/nats-io/nats-serverfrom 0
• Go/github.com/nats-io/nats-serverfrom 0
• Go/github.com/nats-io/nats-server/v2from 0, < 2.11.15
• Go/github.com/nats-io/nats-server/v2from 0, < 2.11.15, >= 2.12.0-RC.1, < 2.12.6

CVSS scores

References (5)

• ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-33218
• ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-33218
• PATCHhttps://github.com/nats-io/nats-server
• WEBhttps://advisories.nats.io/CVE/secnote-2026-10.txt
• WEBhttps://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339