The vulnerability is a use‑after‑free condition (CWE‑416) in NanoMQ 0.24.6. By sending a crafted traffic pattern that mixes high‑frequency publishes with rapid reconnects under the same ClientID and induces massive subscribe/unsubscribe churn, an attacker can trigger a heap‑memory corruption in the broker process. This corruption leads to the broker aborting with SIGABRT, effectively terminating the service and causing a denial of service for all clients.

The weakness exists only in the NanoMQ MQTT Broker from the nanomq project, specifically version 0.24.6. No fixed version is currently available, so all deployments running this version are vulnerable. Until a patched release is issued, users should avoid running the affected edition.

The CVSS base score is 5.3, reflecting a moderate impact. EPSS is under 1 %, indicating a very low likelihood of exploitation in the wild at present. The vulnerability is not in the CISA KEV catalog. An attacker requires the ability to place MQTT traffic on the broker, so the path is remote but limited to clients with network reach to the broker. The lack of a publicly released fix means the priority for addressing the issue is to implement mitigation controls rather than rely on patching.