diff --git a/core/modules/ckeditor5/js/ckeditor5.js b/core/modules/ckeditor5/js/ckeditor5.js
index ae0cf7149e..a55d58d261 100644
--- a/core/modules/ckeditor5/js/ckeditor5.js
+++ b/core/modules/ckeditor5/js/ckeditor5.js
@@ -389,8 +389,8 @@
 
             const styles = window.getComputedStyle(element);
             const height = element.clientHeight;
-            const marginTop = parseInt(styles.marginTop);
-            const marginBottom = parseInt(styles.marginBottom);
+            const marginTop = parseInt(styles.marginTop, 10);
+            const marginBottom = parseInt(styles.marginBottom, 10);
             const mostMargin =
               marginTop >= marginBottom ? marginTop : marginBottom;