The _xfs_buf_find function in fs/xfs/xfs_buf.c in the Linux kernel before 3.7.6 does not validate block numbers, which allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by leveraging the ability to mount an XFS filesystem containing a metadata inode with an invalid extent map.
Exploitability
AV:LAC:LAu:NImpact
C:PI:PA:P4.6/AV:L/AC:L/Au:N/C:P/I:P/A:P