A flaw was found in grub2. When reading data from a squash4 filesystem, grub's squash4 fs module uses user-controlled parameters from the filesystem geometry to determine the internal buffer size, however, it improperly checks for integer overflows. A maliciously crafted filesystem may lead some of those buffer size calculations to overflow, causing it to perform a grubmalloc() operation with a smaller size than expected. As a result, the directread() will perform a heap based out-of-bounds write during data reading. This flaw may be leveraged to corrupt grub's internal critical data and may result in arbitrary code execution, by-passing secure boot protections.

A flaw was found in the HFS filesystem. When reading an HFS volume's name at grubfsmount(), the HFS filesystem driver performs a strcpy() using the user-provided volume name as input without properly validating the volume name's length. This issue may read to a heap-based out-of-bounds writer, impacting grub's sensitive data integrity and eventually leading to a secure boot protection bypass.

Grub2: fs/hfs: integer overflow may lead to heap based out-of-bounds write

Grub2: udf: heap based buffer overflow in grubudfreadblock() may lead to arbitrary code execution