The path autocompletion feature in Bash 4.4 allows local users to gain privileges via a crafted filename starting with a " (double quote) character and a command substitution metacharacter.
https://lists.gnu.org/archive/html/bug-bash/2017-01/msg00034.html
http://www.securityfocus.com/bid/96136
http://www.openwall.com/lists/oss-security/2017/02/08/3
http://git.savannah.gnu.org/cgit/bash.git/commit/?id=4f747edc625815f449048579f6e65869914dd715