OxygenOS before version 4.0.2, on OnePlus 3 and 3T, has two hidden fastboot oem commands (4F500301 and 4F500302) that allow the attacker to lock/unlock the bootloader, disregarding the 'OEM Unlocking' checkbox, without user confirmation and without a factory reset. This allows for persistent code execution with high privileges (kernel/root) with complete access to user data.

An issue was discovered in ABOOT in OnePlus 3 and 3T OxygenOS before 4.0.2. The attacker can reboot the device into the fastboot mode, which could be done without any authentication. A physical attacker can press the "Volume Up" button during device boot, where an attacker with ADB access can issue the adb reboot bootloader command. Then, the attacker can put the platform's SELinux in permissive mode, which severely weakens it, by issuing: fastboot oem selinux permissive.