Vulnerability Report

CVE-2026-33217

Title: NATS-Server MQTT ACL Bypass

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-33217.

CWE Category CWE-863
Published Date Mar 25, 2026
Modified Date Mar 26, 2026
Exploit Status Not Found
Score 7.1 CVSS v3.1
Exploit Probability (EPSS)
0.04%

Vulnerability Summary

CVE-2026-33217: 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, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Impacted Vendors

L
linuxfoundation 1

Reference Links

https://advisories.nats.io/CVE/secnote-2026-07.txt https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.1
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:L/UI:N/S:U/C:L/I:H/A:N
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
6.5
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:L/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-33217 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

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:L/UI:N/S:U/C:L/I:H/A:N

Affected Stack

No specific products linked.