CVE-2026-33215

NATS is vulnerable to MQTT hijacking via Client ID

CVSS 6.5 MEDIUMEPSS 0.2%CWE-287 CWE-488

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance. Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.

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

Affected products

nats-io · nats-server

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References

https://advisories.nats.io/CVE/secnote-2026-06.tx https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879