    def respond_error(self, context, exception):
        context.respond_server_error()
        stack = traceback.format_exc()
        return """
        <html>
            <body>

                <style>
                    body {
                        font-family: sans-serif;
                        color: #888;
                        text-align: center;
                    }

                    body pre {
                        width: 600px;
                        text-align: left;
                        margin: auto;
                        font-family: monospace;
                    }
                </style>

                <img src="/ajenti:static/main/error.jpeg" />
                <br/>
                <p>
                    Server error
                </p>
                <pre>
%s
                </pre>
            </body>
        </html>
        """ % stack
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.