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CVE-2026-46411— FlashMQ: Client can trigger uncaught exception on FlashMQ 1.26.1 and older

Quick assessment

Affected
halfgaar FlashMQ
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FlashMQ是Wiebe Cazemier个人开发者的一个快速轻量级的MQTT代理服务器。 FlashMQ 1.26.2之前版本存在安全漏洞，该漏洞源于授权客户端可超出写缓冲区的允许超额提交，触发内部安全保护异常，导致服务器中止。

CVSS 6.5 · Medium EPSS 0.30% · P23

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 1

VendorProduct Version RangeStatus
halfgaar FlashMQ < 1.26.2 affected
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I. Basic Information for CVE-2026-46411

Vulnerability Information
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Vulnerability Title
FlashMQ: Client can trigger uncaught exception on FlashMQ 1.26.1 and older
Source: CVE Program / CVE List V5
Vulnerability Description
FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.26.2, authorized clients have the ability to exceed the permitted over-commit of their write buffer and triggering an internal safe-guard exception. This exception was in a path that was not catchable, and therefore causes a server abort. This issue has been patched in version 1.26.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未捕获的异常
Source: CVE Program / CVE List V5
Vulnerability Title
FlashMQ 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FlashMQ是Wiebe Cazemier个人开发者的一个快速轻量级的MQTT代理服务器。 FlashMQ 1.26.2之前版本存在安全漏洞，该漏洞源于授权客户端可超出写缓冲区的允许超额提交，触发内部安全保护异常，导致服务器中止。
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

Vendor Product Affected Versions CPE Subscribe
halfgaar FlashMQ < 1.26.2 -

II. Public POCs for CVE-2026-46411

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III. Intelligence Information for CVE-2026-46411

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Patches & Fixes for CVE-2026-46411 (1)

Vendor Advisories for CVE-2026-46411 (1)

Other References for CVE-2026-46411 (1)

IV. Related Vulnerabilities

Same product: FlashMQ
Same vendor: halfgaar
Same weakness: CWE-248