CVE-2017-5554 (oxygenos)
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.
Source: CVE-2017-5554 (oxygenos)