With OxygenOS before 4.0.3, when a charger is connected to a powered-off OnePlus 3 or 3T device, the platform starts with adbd enabled. Therefore, a malicious charger or a physical attacker can open up, without authorization, an ADB session with the device, in order to further exploit other vulnerabilities and/or exfiltrate sensitive information.

An issue was discovered in OxygenOS before 4.1.0 on OnePlus 3 and 3T devices. The attacker can change the bootmode of the device by issuing the 'fastboot oem boot_mode {rf/wlan/ftm/normal} command' in contradiction to the threat model of Android where the bootloader MUST NOT allow any security-sensitive operation to be run unless the bootloader is unlocked.

An issue was discovered in OxygenOS before 4.0.3 for OnePlus 3 and 3T. The attacker can persistently make the (locked) bootloader start the platform with dm-verity disabled, by issuing the 'fastboot oem disable_dm_verity' command. Having dm-verity disabled, the kernel will not verify the system partition (and any other dm-verity protected partition), which may allow for persistent code execution and privilege escalation.

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.