High severityNVD Advisory· Published Mar 25, 2026· Updated Mar 25, 2026
NATS allows MQTT clients to bypass ACL checks
CVE-2026-33217
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.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/nats-io/nats-server/v2Go | < 2.11.15 | 2.11.15 |
github.com/nats-io/nats-server/v2Go | >= 2.12.0-RC.1, < 2.12.6 | 2.12.6 |
github.com/nats-io/nats-serverGo | >= 0 | — |
Affected products
1- Range: < 2.11.15
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- github.com/advisories/GHSA-jxxm-27vp-c3m5ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-33217ghsaADVISORY
- advisories.nats.io/CVE/secnote-2026-07.txtghsax_refsource_MISCWEB
- github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5ghsax_refsource_CONFIRMWEB
News mentions
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