CVE-2026-33217

Summary

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 Software

VendorProductVersion RangeStatus
nats-ionats-server< 2.11.15affected
nats-ionats-server>= 2.12.0-RC.1, < 2.12.6affected

Weaknesses

  • CWE-863: CWE-863: Incorrect Authorization

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

nats-server: github.com/nats-io/nats-server: NATS-Server: Access control bypass via unapplied ACLs in MQTT namespace

Additional References

References