CVE-2026-95842 Moquette uncaught MQTT command exceptions can terminate shared session event loops
An attacker can cause a denial of service in the Moquette MQTT broker by triggering uncaught exceptions that terminate shared event loops, blocking message processing for multiple clients.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-95842?
CVE-2026-95842 is a high-severity denial of service vulnerability in moquette-io moquette, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Moquette is a lightweight Java MQTT broker. Prior to 0.18.1, SessionEventLoop.run catches only InterruptedException, and SessionEventLoopGroup does not restart a terminated loop. An MQTT command that raises an uncaught exception can terminate an event loop shared by multiple client sessions, preventing every co-located client from processing PUBLISH, SUBSCRIBE, PUBACK, and other commands. An attacker can select client IDs that map across the available loops to disrupt session processing for the entire broker. This issue is fixed in version 0.18.1.
Weakness: CWE-248
Which versions are affected by CVE-2026-95842?
It affects 1 product.
Products include Moquette Moquette.
How do I fix CVE-2026-95842?
No fix has been published for CVE-2026-95842 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-95842 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-95842 exists.
Other vulnerabilities in moquette-io moquette
- CVE-2026-85724 Moquette pattern ACL wildcard injection allows cross-tenant authorization bypass
- CVE-2026-95848 Moquette fails open when configured authentication or authorization classes cannot load
- CVE-2026-95847 Moquette client IDs can cause cross-session H2 durable-queue corruption
- CVE-2026-95843 Moquette malformed shared subscriptions can crash command processing
- CVE-2026-95844 Moquette deeply nested MQTT topics can cause stack exhaustion