Vulnerability Description
Aedes is an MQTT broker that can run on any stream server. Prior to 1.1.1, the MQTT broker does not bound topic depth or structural complexity before passing topics through `mqemitter` into `qlobber`. A `PUBLISH`, `SUBSCRIBE`, or registered `Will` message containing an excessively deep topic can reach `qlobber._split_words` in `lib/qlobber.js` and trigger an uncaught `too many words` exception. Calls from `handlers/subscribe.js` and the publishing logic are not protected against that exception, so it escapes to the `Node.js event loop` and terminates the entire broker. The `Will` path is independently reachable when a client disconnects ungracefully: it calls `broker.publish` directly and bypasses the `PUBLISH` handler. An attacker must be able to establish an `MQTT session`, authenticated or unauthenticated according to broker configuration. A successful attack disconnects all legitimate clients and prevents reconnection until the broker process restarts. This issue is fixed in version 1.1.1.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/moscajs/aedes/commit/b9024faa4cb416c4c6980760b4d7f55336315f2d
- https://github.com/moscajs/aedes/releases/tag/v1.1.1
- https://github.com/moscajs/aedes/security/advisories/GHSA-xxqp-5qx8-gj5q
FAQ
What is CVE-2026-63341?
CVE-2026-63341 is a vulnerability with a CVSS score of 7.5 (HIGH). Aedes is an MQTT broker that can run on any stream server. Prior to 1.1.1, the MQTT broker does not bound topic depth or structural complexity before passing topics through `mqemitter` into `qlobber`....
How severe is CVE-2026-63341?
CVE-2026-63341 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-63341?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.