ext/mysqlnd/mysqlnd_wireprotocol.c in PHP before 5.6.26 and 7.x before 7.0.11 does not verify that a BIT field has the UNSIGNED_FLAG flag, which allows remote MySQL servers to cause a denial of service (heap-based buffer overflow) or possibly have unspecified other impact via crafted field metadata.
www.openwall.com/lists/oss-security/2016/09/15/10
www.php.net/ChangeLog-5.php
www.php.net/ChangeLog-7.php
www.securityfocus.com/bid/93005
www.securitytracker.com/id/1036836
access.redhat.com/errata/RHSA-2018:1296
bugs.php.net/bug.php?id=72293
github.com/php/php-src/commit/28f80baf3c53e267c9ce46a2a0fadbb981585132?w=1
security.gentoo.org/glsa/201611-22
www.tenable.com/security/tns-2016-19