Index: paste-1.7.5.1/paste/urlmap.py
===================================================================
--- paste-1.7.5.1.orig/paste/urlmap.py	2017-09-20 14:20:09.000000000 -0400
+++ paste-1.7.5.1/paste/urlmap.py	2017-09-20 14:33:07.234544101 -0400
@@ -119,7 +119,7 @@ class URLMap(DictMixin):
             return domain, url
         assert (not url or url.startswith('/')
                 or self.domain_url_re.search(url)), (
-            "URL fragments must start with / or http:// (you gave %r)" % url)
+            "URL fragments must start with / or http:// (you gave %r)" % cgi.escape(url))
         match = self.domain_url_re.search(url)
         if match:
             url = url[match.end():]