is this HTML input form secure?

i managed to build this form using many sources over internet , and it actually works. But do not know if it is good against any breaks.

        <form action="/some/server/some.cgi" method="POST">
            <fieldset>
                <legend>contact me:</legend>
                <input type="hidden" name="recipient"
               value="some@some.com">
                <input type="hidden" name="subject"
           value="message ">
                <br>
                <br>
                <table>
                    <tr>
                        <td>
                            <input type="text" name="name" 
                 placeholder="Your Name please" size="30"
            maxlength="30" title="Your name (no numbers)" 
         pattern="[a-zA-Z]{2,30}" required>
                        </td>
                    </tr>

                    <tr>
                        <td>

                            <input type="email" value="email"  
           name="email" placeholder="Provide valid email please" 
                 pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,3}$"
                title="Your VALID email address" size="30" 
             maxlength="50" required>

                        </td>
                    </tr>
                    <tr>
                        <td>
                            <input type="text" name="message" 
            placeholder="Message" size="30" maxlength="200"

            title="Long text is not allowed" 
                   pattern="[a-zA-Z0-9\s]{5,200}" required>
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <input type="submit" value="Send" 
                     name="Submit">
                        </td>
                    </tr>
                </table>
            </fieldset>
        </form>

i am new to regEx and would like to know any issues that can happen with this form. thanks