Cross-site scripting (XSS) vulnerability in the WddxPacket::recursiveAddVar function in HHVM (aka the HipHop Virtual Machine) before 3.5.0 allows remote attackers to inject arbitrary web script or HTML via a crafted string to the wddx_serialize_value function.
www.openwall.com/lists/oss-security/2015/04/01/1
www.openwall.com/lists/oss-security/2015/04/07/3
www.securityfocus.com/bid/74061
github.com/facebook/hhvm/commit/324701c9fd31beb4f070f1b7ef78b115fbdfec34
github.com/facebook/hhvm/issues/4283
lists.wikimedia.org/pipermail/mediawiki-announce/2015-March/000175.html
phabricator.wikimedia.org/T85851