Live › vulnerability › CVE-2026-85724
Go to dashboardMoquette is a Java MQTT broker; versions up to 0.18.0 let any connected client (anonymous by default) bypass pattern-based ACLs by putting +/# wildcard characters in its clientId, reading and writing other tenants' topics, and also crash the whole broker with malformed shared-subscription or nested-topic input. An attacker also gets unauthorized Last-Will publishes and can corrupt another client's persistent queue state.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
| Product | Ecosystem | Affected | Fixed in |
|---|---|---|---|
| io.moquette:moquette-broker | maven | <= 0.18.0 | 0.18.1 |
| moquette | vendor | < 0.18.1 | 0.18.1 |
0.18.0 or lower0.18.1Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
moquette is reachable by untrusted MQTT clients (anonymous by default), so every byte from any client, including pre-authentication, is untrusted. This is a memory-safe JVM: the ceiling is authorization/ACL bypass + denial of service + cross-session integrity, not RCE (I did not find one and do not claim one). Audited at commit da7f719a6bab9829d520b5838e13ea7b1f9be3ef, module broker/.
pattern-based ACLs across tenants. In AuthorizationsCollector.canDoOperation (AuthorizationsCollector.java:116-131, esp. line 123) the clientId/username is substituted raw into a pattern ACL rule and then wildcard-matched, and the clientId is never validated for MQTT wildcard characters +/# at CONNECT (MQTTConnection.processConnect):Topic substitutedTopic = new Topic(auth.topic.toString().replace("%c", client).replace("%u", username)); if (topic.match(substitutedTopic)) return true;
A client that connects with clientId + turns sensor/%c/# into the filter sensor/+/#, gaining cross-tenant read AND write. (Precondition: pattern ACL rules configured — a common multi-tenant setup.)
(High) Crash the whole broker. SessionEventLoop (SessionEventLoop.java:40-54) catches only InterruptedException and is never restarted (SessionEventLoopGroup), so any uncaught exception on it wedges every co-located client. Trivially reachable inputs: malformed $share/grp SUBSCRIBE (SharedSubscriptionUtils.extractShareName -> StringIndexOutOfBoundsException), deeply nested topic (CTrie recursion -> StackOverflowError), and ACL NPE below. Unbounded subscriptions / retained / in-flight / topic-alias / interceptor state (BrokerInterceptor uses an unbounded queue) also allow OOM; durable stores allow disk exhaustion.
(High) NPE in ACL sink on clientId # (invalid filter sensor/#/# -> null tokens -> Topic.match NPE at Topic.java:173).
(High) Will-message authorization bypass. Last-Will topic is published (PostOffice.publishWill) without canWrite/reserved-topic checks used for normal PUBLISH.
(Medium) Cross-session durable corruption. H2PersistentQueue opens queue_"+clientId and queue_"+clientId+"_meta; client id sensor_meta collides with victim sensor metadata map -> corrupts head/tail.
(Medium) Fail-open if authenticator/authorizator class fails to load -> PermitAll/AcceptAll (Server.java:483-531).
Source-only, no network; PoCs run on JDK 17:
Cross-tenant eavesdropping and injection, whole-broker DoS, unauthorized Will publishes, and cross-session durable corruption.
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