---
cve: "CVE-2026-47275"
severity: "LOW"
cvss: 2.6
epss: "17%"
vendor: "nanomq"
kev: false
exploited: false
published: "2026-07-20 17:17:10"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-09-15T11:47:38+02:00"
---

# CVE-2026-47275

> 2.6 LOW · 🧪 PoC

## Beschreibung

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-Vektor

```
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Gering | warn |
| UI Interaktion | Erforderlich | good |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Keine | good |
| I Integrität | Keine | good |
| A Verfügbarkeit | Gering | warn |

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-47275) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_