diff --git a/lib/url.c b/lib/url.c
index ee3d176d9612e659a8f14679b4828c0b402b6f8e..f033dbc9566412c406bd8986e1c7cccb92e4be2c 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -3627,7 +3627,7 @@ static void fix_hostname(struct SessionHandle *data,
   host->dispname = host->name;
 
   len = strlen(host->name);
-  if(host->name[len-1] == '.')
+  if(len && (host->name[len-1] == '.'))
     /* strip off a single trailing dot if present, primarily for SNI but
        there's no use for it */
     host->name[len-1]=0;