diff --git a/Components/Sources/ComponentsObjC/WKSourceEditorFormatter.m b/Components/Sources/ComponentsObjC/WKSourceEditorFormatter.m
index c110cccd765..f7351f00785 100644
--- a/Components/Sources/ComponentsObjC/WKSourceEditorFormatter.m
+++ b/Components/Sources/ComponentsObjC/WKSourceEditorFormatter.m
@@ -36,6 +36,10 @@ - (BOOL)canEvaluateAttributedString: (NSAttributedString *)attributedString agai
         return NO;
     }
     
+    if (attributedString.length <= range.location) {
+        return NO;
+    }
+    
     if (attributedString.length < (range.location + range.length)) {
         return NO;
     }