CVE-2026-51721

Deferred Deferred - Pending Action

Incorrect Access Control in TOTOLINK T6 Firmware

Publication date: 2026-08-31

Last updated on: 2026-09-01

Assigner: MITRE

Description

Incorrect access control in the setPairCfg function of TOTOLINK T6 4.1.5cu.748_B20211015 allows unauthenticated attackers to alter the mesh pairing state via sending a crafted POST request to /cgi-bin/cstecgi.cgi.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-31

Last Modified

2026-09-01

Generated

2026-09-21

AI Q&A

2026-08-31

EPSS Evaluated

2026-09-15

NVD

CVE-2026-51721

EUVD

EUVD-2026-68674

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 setPairCfg function of TOTOLINK T6 firmware version 4.1.5cu.748_B20211015. It allows unauthenticated attackers to change the mesh pairing state by sending a specially crafted POST request to the vulnerable endpoint /cgi-bin/cstecgi.cgi.

Detection Guidance

To detect this vulnerability, monitor network traffic for POST requests sent to /cgi-bin/cstecgi.cgi with parameters targeting the setPairCfg function. Check for unauthenticated access attempts to this endpoint.

Impact Analysis

An attacker could exploit this to alter the mesh pairing state of your TOTOLINK T6 device without authentication. This may disrupt network connectivity or allow unauthorized access to connected devices in a mesh network setup.

Compliance Impact

This vulnerability allows unauthenticated attackers to retrieve sensitive DHCP lease configuration details, which could include network device information. Such unauthorized access may violate data protection requirements under GDPR (e.g., unauthorized data access) and HIPAA (e.g., exposure of networked device configurations).

Mitigation Strategies

Immediately update the TOTOLINK T6 firmware to the latest version. Restrict access to the /cgi-bin/cstecgi.cgi endpoint via network firewall rules. Disable unnecessary services and monitor for suspicious POST requests.

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