diff --git a/src/userSync.js b/src/userSync.js
index fceeb1d722d9..f653880fa29f 100644
--- a/src/userSync.js
+++ b/src/userSync.js
@@ -225,7 +225,7 @@ export function newUserSync(userSyncDependencies) {
       }
       return checkForFiltering[filterType](biddersToFilter, bidder);
     }
-    return false;
+    return !permittedPixels[type];
   }
 
   /**
diff --git a/test/spec/userSync_spec.js b/test/spec/userSync_spec.js
index 2b68349ca31e..55b613ce9293 100644
--- a/test/spec/userSync_spec.js
+++ b/test/spec/userSync_spec.js
@@ -475,6 +475,24 @@ describe('user sync', function () {
           });
           expect(userSync.canBidderRegisterSync('iframe', 'otherTestBidder')).to.equal(false);
         });
+        it('should return false for iframe if there is no iframe filterSettings', function () {
+          const userSync = newUserSync({
+            config: {
+              syncEnabled: true,
+              filterSettings: {
+                image: {
+                  bidders: '*',
+                  filter: 'include'
+                }
+              },
+              syncsPerBidder: 5,
+              syncDelay: 3000,
+              auctionDelay: 0
+            }
+          });
+
+          expect(userSync.canBidderRegisterSync('iframe', 'otherTestBidder')).to.equal(false);
+        });
         it('should return true if filter settings does allow it', function () {
           const userSync = newUserSync({
             config: {