diff --git a/browser/base/content/test/browser_urlHighlight.js b/browser/base/content/test/browser_urlHighlight.js
index 73903da6e25..3ab31273841 100644
--- a/browser/base/content/test/browser_urlHighlight.js
+++ b/browser/base/content/test/browser_urlHighlight.js
@@ -62,6 +62,8 @@ function test() {
   testVal("<https://>mozilla.org</sub/file.ext?foo&bar#top>");
 
   testVal("<https://sub.>mozilla.org<:666/file.ext>");
+  testVal("<sub.>mozilla.org<:666/file.ext>");
+  testVal("localhost<:666/file.ext>");
 
   let IPs = ["192.168.1.1",
              "[::]",
@@ -87,6 +89,7 @@ function test() {
   IPs.forEach(function (IP) {
     testVal(IP);
     testVal(IP + "</file.ext>");
+    testVal(IP + "<:666/file.ext>");
     testVal("<https://>" + IP);
     testVal("<https://>" + IP + "</file.ext>");
     testVal("<https://user:pass@>" + IP + "<:666/file.ext>");
diff --git a/browser/base/content/urlbarBindings.xml b/browser/base/content/urlbarBindings.xml
index aaa9c62d7ce..2e65ee5e931 100644
--- a/browser/base/content/urlbarBindings.xml
+++ b/browser/base/content/urlbarBindings.xml
@@ -204,7 +204,7 @@
           let textNode = this.editor.rootElement.firstChild;
           let value = textNode.textContent;
 
-          let protocol = value.match(/^[a-z\d.+\-]+:/);
+          let protocol = value.match(/^[a-z\d.+\-]+:(?=[^\d])/);
           if (protocol &&
               ["http:", "https:", "ftp:"].indexOf(protocol[0]) == -1)
             return;