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TI-2026-34855 Aliases CVE-2026-47275

nanomq NULL Pointer Dereference in MQTTv5 Client CONNECT Decoder Leading to Remote DoS

Priority MEDIUM 46CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
High
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-476.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00273 19th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nanomqnanomqup to 0.24.11—No fix listedCNA
  • nanomq Vendornanomq Affected up to 0.24.11 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:emqx:nanomq:*:*:*:*:*:*:*:*——nanomq
  • cpe:2.3:a:emqx:nanomq:*:*:*:*:*:*:*:* Versions — — ·nanomq

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-47275

References

Other 1

  • TI-2026-24672 NanoMQ has Heap Buffer Overflow in URI Parameter Parsing CVSS 4.0HIGH 7.7
  • TI-2024-28570 An access control issue in NanoMQ v0.21.10 allows attackers to bypass security… CVSS 3.1HIGH 8.8
  • TI-2026-27853 An issue in EMQ NanoMQ v.0.24.9 allows a remote attacker to cause a denial of service via… CVSS 3.1HIGH 7.5
  • TI-2026-17589 MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer() CVSS 3.1HIGH 7.5
  • TI-2024-20452 Null Pointer Dereference vulnerability in topic_filtern function in mqtt_parser.c in… CVSS 3.1HIGH 7.5
  • TI-2023-17307 NanoMQ 0.16.5 is vulnerable to heap-use-after-free in the nano_ctx_send function of nmq_mqtt.c. CVSS 3.1HIGH 7.5
See all 52 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences