The zend_inline_hash_func function in php-luasandbox in the Scribuntu extension for MediaWiki before 1.19.10 1.2x before 1.21.4 and 1.22.x before 1.22.1 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via vectors related to converting Lua data structures to PHP as demonstrated by passing { {} = 1 } to a module function.