CVE-2026-33218

Severity CVSS v4.0:

Pending analysis

Type:

CWE-20 Input Validation

Publication date:

25/03/2026

Last modified:

26/03/2026

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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 7.50 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x

7.50

Severity 3.x

HIGH

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:linuxfoundation:nats-server::::::::		2.11.15 (excluding)
cpe:2.3:a:linuxfoundation:nats-server::::::::	2.12.0 (including)	2.12.6 (excluding)

To consult the complete list of CPE names with products and versions, see this page

CVE-2026-33218

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools