diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index c186576..8de32ed 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -515,7 +515,7 @@ function _filter_url($text, $filter) {
   // 1. Allow =&# for empty URL parameters and other URL-join artifacts
   $valid_url_ending_characters = '[\p{L}\p{M}\p{N}:_+~#=/]|(?:' . $valid_url_balanced_parens . ')';
 
-  $valid_url_query_chars = '[a-z0-9!?\*\'@\(\);:&=\+\$\/%#\[\]\-_\.,~|]';
+  $valid_url_query_chars = '[a-zA-Z0-9!?\*\'@\(\);:&=\+\$\/%#\[\]\-_\.,~|]';
   $valid_url_query_ending_chars = '[a-z0-9_&=#\/]';
 
   //full path