TYPO3 Core

I noticed the same problem with umlauts in URLs.
My suggestion for the patch would be:

somewhere else:

$IDN = new idna_convert(array('idn_version' => 2008));

for class.t3lib_div:

/**
 * Checking syntax of input email address
 *
 * @param string $email Input string to evaluate
 * @return boolean Returns TRUE if the $email address (input string) is valid
 */
public static function validEmail($email) {
        // enforce maximum length to prevent libpcre recursion crash bug #52929 in PHP
        // fixed in PHP 5.3.4; length restriction per SMTP RFC 2821
    if (strlen($email) > 320) {
        return FALSE;
    }
    return (filter_var($IDN->encode($email), FILTER_VALIDATE_EMAIL) !== FALSE);
}

/**
 * Checks if a given string is a Uniform Resource Locator (URL).
 *
 * @param string $url The URL to be validated
 * @return boolean Whether the given URL is valid
 */
public static function isValidUrl($url) {
    return (filter_var($IDN->encode($url), FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED) !== FALSE);
}

Hi David. Your proposal seems fine to me, could you maybe make this into a patch/review-request?
idna_convert.class.php is already available in typo3/contrib/idna for #14500.

Patch set 1 of change Iaff6d43c54ce4a2567b46acfe449e33b89136f8d has been pushed to the review server.
It is available at http://review.typo3.org/6907

Applied in changeset 6a1632ec35deecfcd7179ce4ad52efcff667d3f2.

Patch set 2 for branch TYPO3_4-6 has been pushed to the review server.
It is available at http://review.typo3.org/9435

Applied in changeset c4239fa00a326f20c49d74cfb32cda495fcc8b41.