CVE-2026-33215

NATS is vulnerable to MQTT hijacking via Client ID

Published Mar 24, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-fcjp-h8cc-6879 NATS is vulnerable to MQTT hijacking via Client ID
History
Type Values Removed Values Added
First Time appeared Linuxfoundation
Linuxfoundation nats-server
CPEs cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*
Vendors & Products Linuxfoundation
Linuxfoundation nats-server
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Nats
Nats nats Server
Vendors & Products Nats
Nats nats Server
Type Values Removed Values Added
Description NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.
Title NATS is vulnerable to MQTT hijacking via Client ID
Weaknesses CWE-287
CWE-488
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Mar 25, 2026, 1:05 PM
Reserved
Mar 17, 2026, 11:23 PM
Status
Analyzed
Published
Mar 24, 2026, 9:16 PM
Modified
Jun 17, 2026, 10:37 AM
Severity
Moderate
Public date
Mar 24, 2026, 8:55 PM