diff --git a/libraries/joomla/filter/input.php b/libraries/joomla/filter/input.php
index 2f9579dad1dc7..34777ee9787ec 100644
--- a/libraries/joomla/filter/input.php
+++ b/libraries/joomla/filter/input.php
@@ -1103,7 +1103,7 @@ protected function escapeAttributeValues($source)
 				// We have a closing quote, convert its byte position to a UTF-8 string length, using non-multibyte substr()
 				$stringBeforeQuote = substr($attributeValueRemainder, 0, $matches[0][1]);
 				$closeQuoteChars = StringHelper::strlen($stringBeforeQuote);
-				$nextAfter = $nextBefore + $matches[0][1];
+				$nextAfter = $nextBefore + $closeQuoteChars;
 			}
 			else
 			{
diff --git a/tests/unit/suites/libraries/joomla/filter/JFilterInputTest.php b/tests/unit/suites/libraries/joomla/filter/JFilterInputTest.php
index 874b7527f9c1b..f6bd6297b66da 100644
--- a/tests/unit/suites/libraries/joomla/filter/JFilterInputTest.php
+++ b/tests/unit/suites/libraries/joomla/filter/JFilterInputTest.php
@@ -1294,6 +1294,12 @@ public function blacklist()
 				'<img src="xxx" height="zzz" />',
 				'Test empty alt attribute'
 			),
+			'infinte_loop_c' => array(
+				'string',
+				'<hr title="Äußerungen" class="system-pagebreak" alt="Äußerungen" />',
+				'<hr title="Äußerungen" class="system-pagebreak" alt="Äußerungen" />',
+				'Test correct position of close quote in UTF-8 value'
+			),
 			'quotes_in_text' => array(
 				'string',
 				$quotesInText1,