A flaw was found in CryptoPro Secure Disk bootloaders before 2022-06-01. An attacker may use this bootloader to bypass or tamper with Secure Boot protections. In order to load and execute arbitrary code in the pre-boot stage, an attacker simply needs to replace the existing signed bootloader currently in use with this bootloader. Access to the EFI System Partition is required for booting using external media.