An issue was discovered in the Linux kernel through 4.17.10. There is an invalid pointer dereference in io_ctl_map_page() when mounting and operating a crafted btrfs image, because of a lack of block group item validation in check_leaf_item in fs/btrfs/tree-checker.c. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-14613
