A certain Debian patch for GNU GRUB uses world-readable permissions for grub.cfg, which allows local users to obtain password hashes, as demonstrated by reading the passwordpbkdf2 directive in the file.

Grub Legacy 0.97 and earlier stores pre-boot authentication passwords in the BIOS Keyboard buffer and does not clear this buffer before and after use, which allows local users to obtain sensitive information by reading the physical memory locations associated with this buffer.