CVE-2009-4307 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2009-4307): The ext4_fill_flex_info function in fs/ext4/super.c in the Linux kernel before 2.6.32-git6 allows user-assisted remote attackers to cause a denial of service (divide-by-zero error and panic) via a malformed ext4 filesystem containing a super block with a large FLEX_BG group size (aka s_log_groups_per_flex value).