CVE-2026-51664

Deferred Deferred - Pending Action

Incorrect Access Control in TOTOLINK T6 Firmware

Publication date: 2026-08-28

Last updated on: 2026-09-01

Assigner: MITRE

Description

Incorrect access control in the getTelnetCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to obtain Telnet service enablement status information via sending a crafted POST request to /cgi-bin/cstecgi.cgi.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-28

Last Modified

2026-09-01

Generated

2026-09-18

AI Q&A

2026-08-29

EPSS Evaluated

2026-09-15

NVD

CVE-2026-51664

EUVD

EUVD-2026-68008

Affected Vendors & Products

Vendor	Product	Version / Range
totolink	t6	4.1.5cu.748_b20211015

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-284	The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Attack-Flow Graph

Executive Summary

This vulnerability is an incorrect access control issue in the getTelnetCfg function of TOTOLINK T6 firmware version 4.1.5cu.748_B20211015. It allows unauthenticated attackers to check if the Telnet service is enabled on the device by sending a specially crafted POST request to /cgi-bin/cstecgi.cgi.

Detection Guidance

To detect this vulnerability, check if the TOTOLINK T6 device is running firmware version 4.1.5cu.748_B20211015 or similar. Send a crafted POST request to /cgi-bin/cstecgi.cgi targeting the getTelnetCfg function and observe if it reveals Telnet service status without authentication.

Impact Analysis

An attacker could exploit this to gather information about the device's Telnet status without authentication. This could be a first step in further attacks if Telnet is enabled, potentially leading to unauthorized access or control of the device.

Compliance Impact

This vulnerability allows unauthenticated attackers to obtain Telnet service enablement status information via crafted POST requests. While not directly impacting GDPR or HIPAA compliance, unauthorized access to network services could lead to data breaches or unauthorized system access, which may violate these regulations if sensitive data is exposed or compromised.

Mitigation Strategies

Immediately update the TOTOLINK T6 firmware to the latest patched version. Disable Telnet service if not required. Restrict access to the device's web interface via network segmentation or firewall rules.

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