vBSEO is the leading SEO Plugin for vBulletin. There is a vulnerability in the 'proc_deutf()' function defined in /includes/functions_vbseocp_abstract.php. User input passed through 'char_repl' POST parameter isn't properly sanitized before being used in a call to preg_replace() function which uses the 'e' modifier. This can be exploited to inject and execute arbitrary code leveraging the PHP's complex curly syntax.
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