Vulnerability Description
In nanomq versions 0.24.11 and earlier, a NULL pointer dereference in `nni_mqttv5_msg_decode_connect()` allows a malicious MQTT broker to crash any connecting NanoMQ MQTTv5 client (including bridge mode) with a single packet, causing remote denial of service via SIGSEGV. In `nni_mqttv5_msg_decode_connect()` (`mqtt_codec.c:1863`), the code iterates over CONNECT properties using variable `prop` when it should use `will_prop`. When a CONNECT packet has no connect-level properties (`prop == NULL`) but has will properties (`will_prop != NULL`), dereferencing `prop->next` causes SIGSEGV at address `0x38` (NULL + `offsetof(property, next)`). This affects both `nanomq_cli` and **NanoMQ bridge mode** (Core component), as both use the same `mqtt_client.c` receive path. This can lead to remote DoS if a malicious MQTT broker can crash the client process with a single 35-byte packet and persistent DoS if auto-reconnect causes infinite crash loop.
CVSS Score
LOW
Related Weaknesses (CWE)
References
- https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6
- https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6
FAQ
What is CVE-2026-47275?
CVE-2026-47275 is a vulnerability with a CVSS score of 2.6 (LOW). In nanomq versions 0.24.11 and earlier, a NULL pointer dereference in `nni_mqttv5_msg_decode_connect()` allows a malicious MQTT broker to crash any connecting NanoMQ MQTTv5 client (including bridge mo...
How severe is CVE-2026-47275?
CVE-2026-47275 has been rated LOW with a CVSS base score of 2.6/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-47275?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.