TYPO3 Core

$h is read before it is initialized:

public static function normalizeIPv6($address)    {
        $normalizedAddress = '';
        $stageOneAddress = '';

$chunks = explode('::', $address);    // Count 2 if if address has hidden zero blocks
        if (count($chunks)==2)    {
            $chunksLeft = explode(':', $chunks[0]);
            $chunksRight = explode(':', $chunks[1]);
            $left = count($chunksLeft);
            $right = count($chunksRight);

// Special case: leading zero-only blocks count to 1, should be 0
            if ($left==1 && strlen($chunksLeft[0])==0)    $left=0;

$hiddenBlocks = 8 - ($left + $right);
            $hiddenPart = '';
            while ($h<$hiddenBlocks)    {
                $hiddenPart .= '0000:';
                $h++;
            }

(issue imported from #M14915)