diff --git a/src/Symfony/Component/Console/Helper/DialogHelper.php b/src/Symfony/Component/Console/Helper/DialogHelper.php
index 6a442ea376..57f6a6f6b4 100644
--- a/src/Symfony/Component/Console/Helper/DialogHelper.php
+++ b/src/Symfony/Component/Console/Helper/DialogHelper.php
@@ -150,7 +150,7 @@ class DialogHelper extends Helper
                     $c .= fread($inputStream, 2);
 
                     // A = Up Arrow. B = Down Arrow
-                    if ('A' === $c[2] || 'B' === $c[2]) {
+                    if (isset($c[2]) && ('A' === $c[2] || 'B' === $c[2])) {
                         if ('A' === $c[2] && -1 === $ofs) {
                             $ofs = 0;
                         }