NATS allows MQTT clients to bypass ACL checks_CVE-2026-33217

7.1 / 10

HIGH

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

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, 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.

Basic Information

ID CVE-2026-33217

Source GitHub_M

Published Mar 25, 2026 at 19:43

Modified Mar 25, 2026 at 20:08

Affected Product

Vendor nats-io

Product nats-server

Version < 2.11.15

Affected Versions nats-io nats-server < 2.11.15
nats-io nats-server >= 2.12.0-RC.1, < 2.12.6

CWE Classification

CWE-863

References

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    "published": "2026-03-25T19:43:40.969Z",
    "modified": "2026-03-25T20:08:22.861Z",
    "type": "cve",
    "title": "NATS allows MQTT clients to bypass ACL checks",
    "source": "GitHub_M",
    "references": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5\nhttps://advisories.nats.io/CVE/secnote-2026-07.txt",
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