Vulnerability Report

CVE-2026-33218

Title: NATS-Server Leafnode Port Pre-authentication Crash

Input Validation Error

Proof Of Concept

No public PoC currently indexed for CVE-2026-33218.

CWE Category CWE-20

Published Date Mar 25, 2026

Modified Date Mar 26, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.07%

Vulnerability Summary

CVE-2026-33218: 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.

Impacted Vendors

linuxfoundation 1

Reference Links

https://advisories.nats.io/CVE/secnote-2026-10.txt https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-33218 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

March 26, 2026 MODIFIED

Vulnerability data updated via NVD.

March 26, 2026 MODIFIED

Vulnerability data updated via NVD.

March 26, 2026 MODIFIED

Vulnerability data updated via NVD.

March 25, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Stack

No specific products linked.