CVE-2026-95843 Moquette malformed shared subscriptions can crash command processing
A remote attacker can crash the MQTT broker's command processing loop by sending a malformed shared subscription filter, denying service to other 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-2026-95843?
CVE-2026-95843 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, PostOffice.subscribe parses a shared-subscription filter through SharedSubscriptionUtils.extractShareName before validating the complete $share/{shareName}/{topicFilter} structure. A remote client can send a filter such as $share/grp without a topic-filter portion, causing a StringIndexOutOfBoundsException while calculating the share name. The exception terminates command handling on the shared session event loop and can deny service to other client sessions assigned to that loop. This issue is fixed in version 0.18.1.
Weakness: CWE-20
Which versions are affected by CVE-2026-95843?
It affects 1 product.
Products include Moquette Moquette.
How do I fix CVE-2026-95843?
No fix has been published for CVE-2026-95843 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-2026-95843 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-95843 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-2026-95842 Moquette uncaught MQTT command exceptions can terminate shared session event loops
- CVE-2026-95844 Moquette deeply nested MQTT topics can cause stack exhaustion