if you accidently forgot to disable magic quotes :)

silex_magic_quotes_fix.php

<?php

// magic quotes fix.
$app->after(function (
	\Symfony\Component\HttpFoundation\Request $request,
	\Symfony\Component\HttpFoundation\Response $response
) {
	$content_type = $response->headers->get('content-type');
	if (strpos($content_type, 'text/html') === 0) {
		$response->setContent(preg_replace_callback('@(?<attribute>[a-z0-9]+)=(\\\\(?<enclosure>["|\']))(?<value>[^"\']+)\2@i',
			function ($matches) {
				$vals = array_combine(array_map(function ($key) {
					return "%$key%";
				}, array_keys($matches)), $matches);

				return strtr('%attribute%=%enclosure%%value%%enclosure%', $vals);
			}, $response->getContent()));
	}
});