--- a/b2g/components/TelURIParser.jsm
+++ b/b2g/components/TelURIParser.jsm
@@ -6,21 +6,16 @@
 
 this.EXPORTED_SYMBOLS = ["TelURIParser"];
 
 /**
  * Singleton providing functionality for parsing tel: and sms: URIs
  */
 this.TelURIParser = {
   parseURI: function(scheme, uri) {
-    // Ignore MWI and USSD codes. See 794034.
-    if (uri.indexOf('*') != -1 || uri.indexOf('#') != -1) {
-      return null;
-    }
-
     // https://www.ietf.org/rfc/rfc2806.txt
     let subscriber = uri.slice((scheme + ':').length);
 
     if (!subscriber.length) {
       return null;
     }
 
     let number = '';
@@ -109,12 +104,17 @@ this.TelURIParser = {
       if (subscriber.substring(pos, pos + 15) == ';phone-context=') {
         pos += 15;
 
         // global-network-prefix | local-network-prefix | private-prefi
         number = subscriber.substring(pos, subscriber.length) + number;
       }
     }
 
+    // Ignore MWI and USSD codes. See 794034.
+    if (number.match(/[#\*]/) && !number.match(/^[#\*]\d+$/)) {
+      return null;
+    }
+
     return number || null;
   }
 };
 

new file mode 100644
--- /dev/null
+++ b/b2g/components/test/unit/test_bug832946.js
@@ -0,0 +1,18 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  Components.utils.import("resource:///modules/TelURIParser.jsm")
+
+  // blocked numbers
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:#1234*'), null);
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:*1234#'), null);
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:*1234*'), null);
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:#1234#'), null);
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:*#*#7780#*#*'), null);
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:*1234AB'), null);
+
+  // white list
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:*1234'), '*1234');
+  do_check_eq(TelURIParser.parseURI('tel', 'tel:#1234'), '#1234');
+}

--- a/b2g/components/test/unit/xpcshell.ini
+++ b/b2g/components/test/unit/xpcshell.ini
@@ -1,11 +1,13 @@
 [DEFAULT]
 head =
 tail =
 
 [test_bug793310.js]
 
+[test_bug832946.js]
+
 [test_signintowebsite.js]
 head = head_identity.js
 tail =