7.1High
CVE-2026-33217NATS allows MQTT clients to bypass ACL checks
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.
Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.
Affected products and versions
| Vendor | Product | Versions | |
|---|---|---|---|
| linuxfoundation | nats-server | < 2.11.15 | |
| multicluster globalhub | 1.4 | — | |
| multicluster globalhub | 1.5 | — | |
| multicluster globalhub | 1.6 | — | |
| nats-io | nats-server | < 2.11.15, >= 2.12.0-RC.1, < 2.12.6 | |
| Red Hat | Multicluster Global Hub 1.4.5 | all versions | |
| Red Hat | Multicluster Global Hub 1.6.5 | all versions | |
| Red Hat | Red Hat multicluster global hub 1.5.3 | all versions | |
| Red Hat | Red Hat OpenShift Container Platform 4 | — |
References and patches
- https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5 Vendor Advisory
- https://advisories.nats.io/CVE/secnote-2026-07.txt Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:21769
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/security/cve/CVE-2026-33217
- https://bugzilla.redhat.com/show_bug.cgi?id=2451446
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33217.json
CPE matches (NVD) (2)
cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*< 2.11.15cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*≥ 2.12.0 < 2.12.6