diff --git a/typo3/sysext/core/Classes/Utility/GeneralUtility.php b/typo3/sysext/core/Classes/Utility/GeneralUtility.php
index ef62095c5699471dd249ae94897633aa2f4da638..8e482570fff6b7ecba09f5e03806cbbcb454cb81 100644
--- a/typo3/sysext/core/Classes/Utility/GeneralUtility.php
+++ b/typo3/sysext/core/Classes/Utility/GeneralUtility.php
@@ -914,7 +914,11 @@ class GeneralUtility
         $domain = substr($email, $atPosition + 1);
         $user = substr($email, 0, $atPosition);
         if (!preg_match('/^[a-z0-9.\\-]*$/i', $domain)) {
-            $domain = self::idnaEncode($domain);
+            try {
+                $domain = self::idnaEncode($domain);
+            } catch (\InvalidArgumentException $exception) {
+                return false;
+            }
         }
         return filter_var($user . '@' . $domain, FILTER_VALIDATE_EMAIL) !== false;
     }
@@ -1018,7 +1022,11 @@ class GeneralUtility
             return false;
         }
         if (isset($parsedUrl['host']) && !preg_match('/^[a-z0-9.\\-]*$/i', $parsedUrl['host'])) {
-            $parsedUrl['host'] = self::idnaEncode($parsedUrl['host']);
+            try {
+                $parsedUrl['host'] = self::idnaEncode($parsedUrl['host']);
+            } catch (\InvalidArgumentException $exception) {
+                return false;
+            }
         }
         return filter_var(HttpUtility::buildUrl($parsedUrl), FILTER_VALIDATE_URL) !== false;
     }
diff --git a/typo3/sysext/core/Tests/Unit/Utility/GeneralUtilityTest.php b/typo3/sysext/core/Tests/Unit/Utility/GeneralUtilityTest.php
index 7534fa71d0fb0be7f8e797c44751cb7a9e5a3c78..9b35773d1c239bf2e26c6c049f0bab8d9627a4c4 100644
--- a/typo3/sysext/core/Tests/Unit/Utility/GeneralUtilityTest.php
+++ b/typo3/sysext/core/Tests/Unit/Utility/GeneralUtilityTest.php
@@ -981,7 +981,8 @@ class GeneralUtilityTest extends \TYPO3\TestingFramework\Core\Unit\UnitTestCase
             'trailing carriage return' => ['test@example.com' . CR],
             'trailing linefeed' => ['test@example.com' . LF],
             'trailing carriage return linefeed' => ['test@example.com' . CRLF],
-            'trailing tab' => ['test@example.com' . TAB]
+            'trailing tab' => ['test@example.com' . TAB],
+            'prohibited input characters' => ['“mailto:test@example.com”'],
         ];
     }
 
@@ -1902,6 +1903,7 @@ class GeneralUtilityTest extends \TYPO3\TestingFramework\Core\Unit\UnitTestCase
             'string array()' => ['array()'],
             'random string' => ['qwe'],
             'http directory umlauts' => ['http://www.oebb.at/äöü/'],
+            'prohibited input characters' => ['https://{$unresolved_constant}'],
         ];
     }