Manually apply an improved version of PR #1797 (auto_link() URL helper)
diff --git a/system/helpers/url_helper.php b/system/helpers/url_helper.php
index b1f5ecc..de5bdec 100644
--- a/system/helpers/url_helper.php
+++ b/system/helpers/url_helper.php
@@ -388,40 +388,43 @@
 
 			for ($i = 0, $c = count($matches[0]); $i < $c; $i++)
 			{
-				if (preg_match('|\.$|', $matches[6][$i]))
+				if (preg_match('/(\.|\,)$/i', $matches[6][$i], $m))
 				{
-					$period = '.';
+					$punct = $m[1];
 					$matches[6][$i] = substr($matches[6][$i], 0, -1);
 				}
 				else
 				{
-					$period = '';
+					$punct = '';
 				}
 
 				$str = str_replace($matches[0][$i],
 							$matches[1][$i].'<a href="http'.$matches[4][$i].'://'
 								.$matches[5][$i].$matches[6][$i].'"'.$pop.'>http'
 								.$matches[4][$i].'://'.$matches[5][$i]
-								.$matches[6][$i].'</a>'.$period,
+								.$matches[6][$i].'</a>'.$punct,
 							$str);
 			}
 		}
 
-		if ($type !== 'url' && preg_match_all('/([a-zA-Z0-9_\.\-\+]+)@([a-zA-Z0-9\-]+)\.([a-zA-Z0-9\-\.]*)/i', $str, $matches))
+		if ($type !== 'url' && preg_match_all('/([a-zA-Z0-9_\.\-\+]+)@([a-zA-Z0-9\-]+)\.([a-zA-Z0-9\-\.]+)/i', $str, $matches))
 		{
 			for ($i = 0, $c = count($matches); $i < $c; $i++)
 			{
-				if (preg_match('|\.$|', $matches[3][$i]))
+				if (preg_match('/(\.|\,)$/i', $matches[3][$i], $m))
 				{
-					$period = '.';
+					$punct = $m[1];
 					$matches[3][$i] = substr($matches[3][$i], 0, -1);
 				}
 				else
 				{
-					$period = '';
+					$punct = '';
 				}
 
-				$str = str_replace($matches[0][$i], safe_mailto($matches[1][$i].'@'.$matches[2][$i].'.'.$matches[3][$i]).$period, $str);
+				if (filter_var(($m = $matches[1][$i].'@'.$matches[2][$i].'.'.$matches[3][$i]), FILTER_VALIDATE_EMAIL) !== FALSE)
+				{
+					$str = str_replace($matches[0][$i], safe_mailto($m).$punct, $str);
+				}
 			}
 		}