Add the CSRF token in your template forms:
Jade Template:
form(action='/register', method='POST')
input(type='hidden', name='_csrf', value=_csrf)
input(type='email', name='email', placeholder='Email')
input(type='password', name='password', placeholder='Password')
button(type='submit') Register
EJS Template:
<form action="/register" method="POST">
<input type="hidden" name="_csrf" value="<%= _csrf %>" />
<input type="email" name="email" placeholder="Email" />
<input type="password" name="password" placeholder="Password" />
<button type="submit">Register</button>
</form>