CVE-2026-51768: n/a

This vulnerability arises from improper access control in the setElinkQosConfig function of TOTOLINK T6 firmware 4.1.5cu.748_B20211015. An unauthenticated attacker can exploit this flaw by sending a specially crafted MQTT message to the cs_broker component, enabling modification of privileged Quality of Service (QoS) policies on the master device. The vulnerability is identified as CWE-284 (Improper Access Control) and has a CVSS 3.1 base score of 7.5, reflecting high severity with network attack vector, no privileges required, no user interaction, and impact limited to integrity.

Successful exploitation allows an unauthenticated attacker to modify QoS policies on the master device, potentially disrupting network traffic prioritization and impacting service quality. There is no direct confidentiality or availability impact reported, but integrity of QoS configurations is compromised.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or temporary mitigation has been documented at this time. Until a patch is available, restrict network access to the MQTT broker component if possible and monitor for suspicious MQTT traffic targeting the cs_broker component.