Creammonkey 0.9 through 1.1 and GreaseKit 1.2 through 1.3 does not properly prevent access to dangerous functions, which allows remote attackers to read the configuration, modify the configuration, or send an HTTP request via the (1) GM_addStyle, (2) GM_log, (3) GM_openInTab, (4) GM_setValue, (5) GM_getValue, or (6) GM_xmlhttpRequest function within a web page on which a userscript is configured.