Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-51681 – Unauthenticated WAN Admin Access Exposure – TOTOLINK T6 Router (Firmware 4.1.5cu.74

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-51681 is an incorrect access control vulnerability (CWE-284) in the setRemoteCfg function of the TOTOLINK T6 router web management interface, running firmware 4.1.5cu.748_B20211015. An unauthenticated remote attacker can send a crafted POST request to /cgi-bin/cstecgi.cgi to expose and enable WAN-side administration on the device. The issue carries a CVSS v3.1 base score of 9.1 (Critical).

Technical details

  • Root cause: the setRemoteCfg handler in the device’s CGI-based management interface (cgi-bin/cstecgi.cgi) fails to enforce authentication or authorization checks before processing configuration changes.
  • Trigger condition: an attacker sends a specially crafted HTTP POST request invoking the setRemoteCfg action to the exposed CGI endpoint.
  • Attack vector: network-based, requiring no prior authentication, no privileges, and no user interaction (AV:N/AC:L/PR:N/UI:N).
  • Impact: successful exploitation exposes and can enable WAN-side (internet-facing) remote administration on the router, undermining confidentiality and integrity of the device’s configuration; availability is not affected.

Affected software

  • TOTOLINK T6, firmware version 4.1.5cu.748_B20211015.

Severity

  • CVSS v3.1 Base Score: 9.1 (Critical)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Mitigation and recommended actions

  • Immediate: No vendor-published patched firmware version for this specific CVE has been confirmed at this time; check TOTOLINK’s official download page for the T6 model for updated firmware and apply it as soon as it is available.
  • If no patch: Disable remote/WAN-side administration on the device if not strictly required; restrict access to the router’s management interface (/cgi-bin/cstecgi.cgi) to trusted internal networks only; place management interfaces behind a VPN or firewall rule blocking inbound WAN access; monitor for unexpected changes to remote administration settings.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge