CVE-2026-33217
High
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.
SeverityHigh
CVSS7.1
Exploit probability—
ProductLinuxfoundation Nats-server
PublishedMar 25, 2026
First seenMar 25, 2026
Weakness typeCWE-863Incorrect authorization
How to fix
Update
- linuxfoundation nats-server2.11.15, 2.12.6 or later
- github.com/nats-io/nats-server/v22.11.15, 2.12.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linuxfoundation nats-server | v < 2.11.15, 2.12.0 ≤ v < 2.12.6 | 2.11.15, 2.12.6 |
| github.com/nats-io/nats-server/v2Go | v < 2.11.15, 2.12.0-RC.1 ≤ v < 2.12.6 | 2.11.15, 2.12.6 |
| github.com/nats-io/nats-serverGo | No range specified | — |
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