High advisory for Aedes

Advisory overview

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.

Related 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