Chinese-Made Zbtlink Routers Ship With Backdoor That Opens Unauthenticated Root Shells

Cybersecurity researchers have disclosed details of a "factory-shipped backdoor" implanted in at least 20 Chinese router models from Zbtlink. According to a new report from VulnCheck, the implant appears in all 21 firmware images currently available from Zbtlink that span more than 2 years. The...

CVE-2026-66747

The CVE describes a firmware implant in Zbtlink router firmware (ENDLESSDOORS) embedded as an OpenWrt package (librctl.so) that runs at boot as root under kworker. It does not listen for connections but phones home over cleartext TCP to a hardcoded C2 address on channels 7000/7001, with no authen...