diff --git a/core/modules/filter/filter.module b/core/modules/filter/filter.module
index 217dbc80d03..aa6d16c9c38 100644
--- a/core/modules/filter/filter.module
+++ b/core/modules/filter/filter.module
@@ -515,8 +515,8 @@ 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_ending_chars = '[a-z0-9_&=#\/]';
+  $valid_url_query_chars = '[a-zA-Z0-9!?\*\'@\(\);:&=\+\$\/%#\[\]\-_\.,~|]';
+  $valid_url_query_ending_chars = '[a-zA-Z0-9_&=#\/]';
 
   //full path
   //and allow @ in a url, but only in the middle. Catch things like http://example.com/@user/
diff --git a/core/modules/filter/tests/filter.url-input.txt b/core/modules/filter/tests/filter.url-input.txt
index 7b33af56ca9..92289dcfd16 100644
--- a/core/modules/filter/tests/filter.url-input.txt
+++ b/core/modules/filter/tests/filter.url-input.txt
@@ -10,6 +10,9 @@ http://www.test.com
 www.test.com
 person@test.com
 <code>www.test.com</code>
+http://test.com/?search=test
+http://test.com/?search=Test
+http://test.com/?search=tesT
 
 What about tags that don't exist <x>like x say www.test.com</x>? And what about tag <pooh>beginning www.test.com with p?</pooh>
 
diff --git a/core/modules/filter/tests/filter.url-output.txt b/core/modules/filter/tests/filter.url-output.txt
index 9cc50730886..814a4ed7176 100644
--- a/core/modules/filter/tests/filter.url-output.txt
+++ b/core/modules/filter/tests/filter.url-output.txt
@@ -10,6 +10,9 @@ This is just a <a href="http://www.test.com">www.test.com</a>. paragraph with <a
 <a href="http://www.test.com">www.test.com</a>
 <a href="mailto:person@test.com">person@test.com</a>
 <code>www.test.com</code>
+<a href="http://test.com/?search=test">http://test.com/?search=test</a>
+<a href="http://test.com/?search=Test">http://test.com/?search=Test</a>
+<a href="http://test.com/?search=tesT">http://test.com/?search=tesT</a>
 
 What about tags that don't exist <x>like x say <a href="http://www.test.com">www.test.com</a></x>? And what about tag <pooh>beginning <a href="http://www.test.com">www.test.com</a> with p?</pooh>