Cybersecurity researchers have identified a supply chain attack targeting QuickFox, a VPN tool favored by overseas Chinese users. The attack has reportedly been active since at least August 2025, involving a compromised version of the application that delivers the FDMTP backdoor. This backdoor allows attackers to gain unauthorized access to affected systems, posing significant risks to user privacy and data security. This incident raises concerns about the security of software supply chains, particularly for tools that are essential for users in sensitive environments. Users of QuickFox should be vigilant and consider alternative solutions while the situation is investigated further.