CVE-2026-8686— DoS from MQTT v5.0 Deserialization Fault in core MQTT
Quick assessment
Affected
FreeRTOS coreMQTT
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
coreMQTT Client Library是FreeRTOS开源的一个轻量级客户端通信库。 coreMQTT Client Library 5.0.1之前版本存在缓冲区错误漏洞，该漏洞源于MQTT v5.0属性解析器中缺少边界验证，可能导致MQTT代理通过发送特制数据包造成拒绝服务。
Possible ATT&CK Techniques 1 AI
T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-8686
Vulnerability Information
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Vulnerability Title
DoS from MQTT v5.0 Deserialization Fault in core MQTT
Source: CVE Program / CVE List V5
Vulnerability Description
Missing bounds validation in the MQTT v5.0 property parser in coreMQTT before 5.0.1 allows an MQTT broker to cause a denial of service by sending a crafted packet.
To remediate this issue, users should upgrade to v5.0.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Vulnerability Title
coreMQTT Client Library 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
coreMQTT Client Library是FreeRTOS开源的一个轻量级客户端通信库。 coreMQTT Client Library 5.0.1之前版本存在缓冲区错误漏洞，该漏洞源于MQTT v5.0属性解析器中缺少边界验证，可能导致MQTT代理通过发送特制数据包造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-8686
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
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Qwen3.6-35B-A3B
· 11436 chars
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III. Intelligence Information for CVE-2026-8686
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Vendor Advisories for CVE-2026-8686 (2)
Vendor Pages for CVE-2026-8686 (1)
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V. Comments for CVE-2026-8686
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