diff --git a/src/misc/u2f.ts b/src/misc/u2f.ts
index cb1696c62f..0c178bf62d 100644
--- a/src/misc/u2f.ts
+++ b/src/misc/u2f.ts
@@ -63,7 +63,8 @@ export class U2f {
     }
 
     private validMessage(event: any) {
-        if (!event.origin || event.origin === '' || event.origin !== (this.connectorLink as any).origin) {
+        if (!event.origin || event.origin === '' ||
+            event.origin !== (this.connectorLink as any).origin || !event.data) {
             return false;
         }