The qcow2_open function in the (block/qcow2.c) in QEMU before 1.7.2 and 2.x before 2.0.0 allows local users to cause a denial of service (NULL pointer dereference) via a crafted image which causes an error, related to the initialization of the snapshot_offset and nb_snapshots fields. https://nvd.nist.gov/vuln/detail/CVE-2014-0146