EUVD-2026-68713
GHSA-cf72-3m5m-4j66
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Unauthenticated single-request firmware upload yields full code execution and persistence, so C/I/A all High with no privileges or interaction; network vector gated only by interface reachability.
Primary rating from Vendor (mitre).
CVSS VectorVendor: mitre
Lifecycle Timeline
5DescriptionCVE.org
Incorrect access control in the UploadFirmwareFile function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to upload a crafted firmware image via sending a crafted POST request to /cgi-bin/cstecgi.cgi.
AnalysisAI
Unauthenticated firmware upload in TOTOLINK T6 routers (firmware 4.1.5cu.748_B20211015) lets remote attackers push a crafted firmware image via the UploadFirmwareFile handler in /cgi-bin/cstecgi.cgi without any credentials. Because the device applies attacker-supplied firmware, this is effectively a full-device-takeover primitive yielding persistent code execution. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires reachability of the TOTOLINK T6 HTTP management interface and the ability to send a POST request to the UploadFirmwareFile action of /cgi-bin/cstecgi.cgi; no authentication, credentials, or user interaction are needed (PR:N/UI:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N, C:H/I:H/A:H = 9.8) is well-matched to this vulnerability class: unauthenticated firmware replacement genuinely delivers full confidentiality, integrity, and availability loss, unlike the read-only TOTOLINK getter CVEs where C:H is overstated. … 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 fixed firmware version is identified at time of analysis; monitor the TOTOLINK download portal (https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/190/ids/36.html) for an updated T6 build and apply it once published. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, conduct an inventory of all TOTOLINK T6 routers in production environments and identify models running firmware 4.1.5cu.748_B20211015 or earlier; immediately segment these devices on isolated VLANs with restricted management access and enable centralized logging of all device changes. …
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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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