An authentication bypass flaw was found in GRUB due to the way that GRUB uses the UUID of a device to search for the configuration file that contains the password hash for the GRUB password protection feature. An attacker capable of attaching an external drive such as a USB stick containing a file system with a duplicate UUID (the same as in the "/boot/" file system) can bypass the GRUB password protection feature on UEFI systems, which enumerate removable drives before non-removable ones. This issue was introduced in a downstream patch in Red Hat's version of grub2 and does not affect the upstream package.

An out-of-bounds write flaw was found in grub2's NTFS filesystem driver. This issue may allow an attacker to present a specially crafted NTFS filesystem image, leading to grub's heap metadata corruption. In some circumstances, the attack may also corrupt the UEFI firmware heap metadata. As a result, arbitrary code execution and secure boot protection bypass may be achieved.