The ext4_fill_flex_info function in fs/ext4/super.c in the Linux kernel
before 3.2.2, on the x86 platform and unspecified other platforms, allows
user-assisted remote attackers to trigger inconsistent filesystem-groups
data and possibly cause a denial of service via a malformed ext4 filesystem
containing a super block with a large FLEX_BG group size (aka
s_log_groups_per_flex value). NOTE: this vulnerability exists because of
an incomplete fix for CVE-2009-4307.

A flaw was found in the Linux kernel's ext4 file system when mounting a
corrupt filesystem. A user-assisted remote attacker could exploit this flaw
to cause a denial of service.