NanoMQ is a messaging broker/bus for IoT Edge & SDV. Versions prior to 0.24.4 have a buffer overflow case while the PUBLISH packets trigger both shared subscription and vanila subscription. This is fixed in version 0.24.4. As a workaround, disable shared subscription.

Null Pointer Dereference vulnerability in topicfiltern function in mqttparser.c in NanoMQ 0.21.7 allows attackers to cause a denial of service.

A heap-buffer-overflow vulnerability in the readbyte function in NanoMQ v.0.21.7 allows attackers to cause a denial of service via transmission of crafted hexstreams.

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In version 0.24.6, NanoMQ has a protocol parsing / forwarding inconsistency when handling shared subscriptions ($share/). A malformed SUBSCRIBE topic such as $share/ab (missing the second /) is not strictly validated during the subscription stage, so the invalid Topic Filter is stored into the subscription table. Later, when any PUBLISH matches this subscription, the broker send path (nmqpipesendstartv4/v5) performs a second $share/ parsing using strchr() and increments the returned pointer without NULL checks. If the second strchr() returns NULL, subtopic++ turns the pointer into an invalid address (e.g. 0x1). This invalid pointer is then passed into topicfiltern(), which triggers strlen() and crashes with SIGSEGV. The crash is stable and remotely triggerable. This issue has been patched in version 0.24.7.

NanoMQ contains a protocol-semantics flaw in its MQTT v5 SUBSCRIBE handling: if a subscription entry is missing the final 1-byte Subscription Options field, the broker may still accept the malformed packet and install the subscription into internal broker state. Under a specific packet-length construction, the same parser flaw also causes a 1-byte out-of-bounds read that crosses the real heap allocation boundary and is detected by ASAN as a heap-buffer-overflow.

If the consumed byte happens to look acceptable, NanoMQ may continue and append the malformed subscription entry into its internal subinfol state. In that case, a SUBSCRIBE packet that should be rejected by MQTT rules is instead treated as a successful subscription. Whether ASAN reports the bug does not depend on MQTT's logical remain boundary; it depends on whether the read crosses the real heap allocation boundary of the underlying message buffer. In other words, these are not two unrelated issues. They are two manifestations of the same parsing defect: by default, it appears as a semantic vulnerability, and under suitable input conditions, it also becomes a verifiable out-of-bounds read vulnerability.

NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In version 0.24.6, by generating a combined traffic pattern of high-frequency publishes and rapid reconnect/kick-out using the same ClientID and massive subscribe/unsubscribe jitter, it is possible to reliably trigger heap memory corruption in the Broker process, causing it to exit immediately with SIGABRT due to free(): invalid pointer. As of time of publication, no known patched versions are available.

Buffer Overflow vulnerability in the getvarinteger function in mqttparser.c in NanoMQ 0.21.7 allows remote attackers to cause a denial of service via a series of specially crafted hexstreams.