The aufs module for the Linux kernel 3.x and 4.x does not properly maintain POSIX ACL xattr data, which allows local users to gain privileges by leveraging a group-writable setgid directory.Referenceshttp://www.halfdog.net/Security/2016/AufsPrivilegeEscalationInUserNamespaces/http://www.openwall.com/lists/oss-security/2016/02/24/9https://sourceforge.net/p/aufs/mailman/message/34864744/http://www.securityfocus.com/bid/96838
