Uncaught exception in Aedes MQTT broker lets remote clients crash it
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-248.
Summary
Aedes is an MQTT broker from moscajs that is affected before 1.1.1. It does not bound MQTT topic depth or structural complexity, so an excessively deep topic causes an uncaught exception (CWE-248) that terminates the entire broker process. A remote attacker only needs to establish an MQTT session, authenticated or unauthenticated depending on the broker configuration.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade moscajs aedes to version 1.1.1.
Written with Claude Haiku 5.5 from the sources below · 2026-11-05
- Fix · CNA aedes (moscajs) Fixed in 1.1.1
Timeline
- 2026-10-30 Threatist record created from CVE-2026-63341
- 2026-11-01 Priority changed: MEDIUM → LOW
- 2026-11-05 CISA SSVC decision points changed
- 2026-11-05 Priority changed: LOW → HIGH
References
Sources
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