CVE-2026-47275

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 v3 2.6 LOW

2.6^/10

CVSS v3 : LOW

Vector :

Exploitability : 1.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6
https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6

Configurations

No configuration.

History

20 Jul 2026, 19:17

Type	Values Removed	Values Added
References	~~() https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6 -~~	() https://github.com/nanomq/nanomq/security/advisories/GHSA-52qr-3v49-wmx6 -

20 Jul 2026, 17:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-20 17:17

Updated : 2026-07-20 19:17

NVD link : CVE-2026-47275

Mitre link : CVE-2026-47275

CVE.ORG link : CVE-2026-47275

JSON object : View

Products Affected

No product.

CWE

CWE-476

NULL Pointer Dereference

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