The cleanup_journal_tail function in the Journaling Block Device (JBD)
functionality in the Linux kernel 2.6 allows local users to cause a denial
of service (assertion error and kernel oops) via an ext3 or ext4 image with
an "invalid log first block value."

A flaw was found in the Journaling Block Device (JBD). A local attacker
able to mount ext3 or ext4 file systems could exploit this to crash the
system, leading to a denial of service.