fs/pnode.c in the Linux kernel before 4.5.4 does not properly traverse a mount propagation tree in a certain case involving a slave mount, which allows local users to cause a denial of service (NULL pointer dereference and OOPS) via a crafted series of mount system calls.<a href=http://cwe.mitre.org/data/definitions/476.html>CWE-476: NULL Pointer Dereference</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-4581