ext/wddx/wddx.c in PHP before 5.6.25 and 7.x before 7.0.10 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) or possibly have unspecified other impact via a malformed wddxPacket XML document that is mishandled in a wddx_deserialize call, as demonstrated by a tag that lacks a < (less than) character.
http://openwall.com/lists/oss-security/2016/09/02/9
http://rhn.redhat.com/errata/RHSA-2016-2750.html
https://bugs.php.net/bug.php?id=72790
https://github.com/php/php-src/commit/0c8a2a2cd1056b7dc403eacb5d2c0eec6ce47c6f
https://github.com/php/php-src/commit/a14fdb9746262549bbbb96abb87338bacd147e1b?w=1
https://security.gentoo.org/glsa/201611-22
https://www.tenable.com/security/tns-2016-19
http://www.php.net/ChangeLog-5.php