Zbtlink router backdoor discovered

On August 5, 2026, cybersecurity firm VulnCheck disclosed that more than 20 models of routers manufactured by Chinese company Zbtlink (a brand of Shenzhen Zhibotong Electronics) ship with a hidden backdoor dubbed 'Endlessdoors'. The backdoor, discovered by VulnCheck CTO Jacob Baines, automatically communicates with a specific IP address and Chinese-registered domain every 35 seconds, potentially allowing remote attackers to take control of the router and access other devices on the network. Baines estimates at least 100,000 such routers are deployed worldwide. The disclosure adds to Western concerns about cybersecurity risks from Chinese-made networking equipment, following the FCC's March ban on imports of foreign-made routers and United States — Texas's February lawsuit against TP-Link. Zbtlink did not respond to requests for comment, and Reuters could not determine the backdoor's purpose or whether it has been exploited.