---
id: CVE-2026-74232
title: >-
  Zbtlink L3_V2_8 firmware 3.0.0.4.528, Zbtlink WE826-T2 firmware 19.1101,
  Zbtlink ZBT-7628 firmware 1.0.0.2.007, Zbtlink ZBT-ZBT7621 firmware
  1.0.0.3.001, MoreQuick MQAC-7620, MQAC-7620A, MQAP-7620, MQAP-7620A, and
  MQAP-7628 firmware 1.0.…
summary: >-
  Zbtlink L3_V2_8 firmware 3.0.0.4.528, Zbtlink WE826-T2 firmware 19.1101,
  Zbtlink ZBT-7628 firmware 1.0.0.2.007, Zbtlink ZBT-ZBT7621 firmware
  1.0.0.3.001, MoreQuick MQAC-7620, MQAC-7620A, MQAP-7620, MQAP-7620A, and
  MQAP-7628 firmware 1.0.…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-300
  - CWE-506
published: '2026-08-27'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:43:32.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74232'
references:
  - url: 'http://vulncheck.com/blog/zbt-darklantern-speakingstone'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zbtlink-mqwrt-yunmgrd-cloud-c2-implant
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00814
epssPercentile: 0.55159
ingestedAt: '2026-09-24T20:51:40.234Z'
---

## Overview

Zbtlink L3_V2_8 firmware 3.0.0.4.528, Zbtlink WE826-T2 firmware 19.1101, Zbtlink ZBT-7628 firmware 1.0.0.2.007, Zbtlink ZBT-ZBT7621 firmware 1.0.0.3.001, MoreQuick MQAC-7620, MQAC-7620A, MQAP-7620, MQAP-7620A, and MQAP-7628 firmware 1.0.0.2.000, AP522 firmware 1.0.0.2.014, AP7628 and HC5661A firmware 3.0.0.4.380, APG721B firmware 19.0809, HK300 firmware 1.0.0.2.032, and MAP-N10 firmware 1.0.0.2.044 ship a backdoor command-and-control implant (yunmgrd) reachable over an unauthenticated cleartext UDP channel to a hardcoded C2 server. A remote unauthenticated attacker on the network path can hijack the channel and execute arbitrary commands as root. The attacker can also modify DNS entries, exfiltrate PPPoE credentials, and open reverse SSH tunnels.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.