Tuleap before 9.7 allows command injection via the PhpWiki 1.3.10 SyntaxHighlighter plugin. This occurs in the Project Wiki component because the procopen PHP function is used within PhpWiki before 1.5.5 with a syntax value in its first argument, and an authenticated Tuleap user can control this value, even with shell metacharacters, as demonstrated by a '<?plugin SyntaxHighlighter syntax="c;id"' line to execute the id command.