GRUB2 (BFS filesystem parser): Integer overflow producing a heap out-of-bounds read in the BeFS parser

Impact

Integer overflow producing a heap out-of-bounds read in the BeFS parser - leaks bootloader memory, useful for defeating any layout randomisation before pairing with a write primitive.

Who can reach it

Attacker-supplied BFS image.

What to do

grub2 package update + reboot; or strip unused filesystem modules from the GRUB build.

References