EUVD-2026-69201
GHSA-53c4-935x-4h8m
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Triggering firmware flashing impacts device integrity and availability, not confidentiality; C:N/I:H/A:H corrects the provided C:H/I:N/A:N; AC:H retained for MQTT crafting and resident-file prerequisites.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
4DescriptionCVE.org
Incorrect access control in the meshSlaveUpgfw function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to start firmware flashing using existing upgrade files via sending a crafted MQTT message to the cs_broker component.
AnalysisAI
Unauthenticated firmware-flash triggering in TOTOLINK T6 firmware 4.1.5cu.748_B20211015 allows network-accessible attackers to initiate a firmware re-flash cycle by sending crafted MQTT messages to the cs_broker component targeting the meshSlaveUpgfw handler, without any credentials. The root cause is a missing access-control check in the mesh slave upgrade function, enabling any caller on the MQTT network segment to invoke privileged firmware operations. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network access to the TOTOLINK T6's cs_broker MQTT service (default TCP/1883), which is an internal component accessible from the LAN or mesh network segment - it is not typically exposed directly to the WAN. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The provided CVSS 3.1 vector (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N, score 5.9) presents an inconsistency: C:H with I:N and A:N does not align with the described impact of triggering firmware flashing, which inherently affects device integrity and availability rather than confidentiality - this discrepancy should be verified with the vendor. … 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 specific patched firmware version is identified in the available data; consult the TOTOLINK firmware download page at https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/190/ids/36.html for any updated releases and apply the latest firmware if available. … Detailed patch versions, workarounds, and compensating controls in full report. |
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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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