EUVD-2026-69380
GHSA-c6w3-3vcp-m3h3
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Unauthenticated low-complexity MQTT write to config (PR:N/AC:L); action is config tampering so I:H, minor traffic degradation A:L, and no disclosure so C:N.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
4DescriptionCVE.org
Incorrect access control in the sendToMasterQosConfig function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to forward attacker-controlled QoS settings to the master via sending a crafted MQTT message to the cs_broker component..
AnalysisAI
Unauthenticated QoS configuration injection in the TOTOLINK T6 router (firmware 4.1.5cu.748_B20211015) lets remote attackers push attacker-controlled Quality-of-Service settings to the master node by sending a crafted MQTT message to the cs_broker component's sendToMasterQosConfig handler. Because the handler performs no authentication or access-control check, any party able to reach the MQTT broker can alter traffic-shaping/prioritization policy across the managed mesh. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network reachability to the T6's internal MQTT broker (the cs_broker component) and the ability to publish a crafted MQTT message to the sendToMasterQosConfig topic/handler; no credentials, user interaction, or non-default feature toggles are described (PR:N/UI:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The published CVSS 9.8 (AV:N/AC:L/PR:N/UI:N, C:H/I:H/A:H) overstates real-world impact: the described action is forwarding attacker-controlled QoS settings, which is a write/config-tampering primitive affecting integrity (and marginally availability via traffic degradation), not a disclosure of sensitive data - so C:H is not justified by the description; a more defensible impact is C:N/I:H/A:L. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patched firmware version is identified in the available data, so treat mitigation as compensating-control-driven: check the TOTOLINK support/download page (https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/190/ids/36.html) for a firmware build newer than 4.1.5cu.748_B20211015 and apply it if published. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Inventory and identify all TOTOLINK T6 routers in your environment, prioritizing those running firmware 4.1.5cu.748_B20211015; restrict network access to MQTT brokers on affected devices to trusted management networks only and disable remote MQTT access where possible. …
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Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
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External POC / Exploit Code
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