The ext4_fill_super function in fs/ext4/super.c in the Linux kernel 2.6.27 before 2.6.27.19 and 2.6.28 before 2.6.28.7 does not validate the superblock configuration, which allows local users to cause a denial of service (NULL pointer dereference and OOPS) by attempting to mount a crafted ext4 filesystem.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.