diff --git a/core/modules/ckeditor/js/plugins/drupalimage/plugin.js b/core/modules/ckeditor/js/plugins/drupalimage/plugin.js
index 3e45eff..51b6466 100644
--- a/core/modules/ckeditor/js/plugins/drupalimage/plugin.js
+++ b/core/modules/ckeditor/js/plugins/drupalimage/plugin.js
@@ -41,12 +41,27 @@
             'data-entity-uuid': ''
           }
         });
-        widgetDefinition.allowedContent.img.attributes += ',!data-entity-type,!data-entity-uuid';
-        // We don't allow <figure>, <figcaption>, <div> or <p>  in our downcast.
-        delete widgetDefinition.allowedContent.figure;
-        delete widgetDefinition.allowedContent.figcaption;
-        delete widgetDefinition.allowedContent.div;
-        delete widgetDefinition.allowedContent.p;
+        var allowedContentDefinition = {
+          element: 'img',
+          attributes: {
+            '!data-entity-type': '',
+            '!data-entity-uuid': ''
+          }
+        };
+        var imgAttributes = widgetDefinition.allowedContent.img.attributes.split(/\s*,\s*/);
+        for (var i = 0; i < imgAttributes.length; i++) {
+          allowedContentDefinition.attributes[imgAttributes[i]] = '';
+        }
+        if (widgetDefinition.allowedContent.img.classes) {
+          allowedContentDefinition.attributes['class'] = widgetDefinition.allowedContent.img.classes.split(/\s*,\s*/).join(' ');
+        }
+        if (widgetDefinition.allowedContent.img.styles) {
+          var imgStyles = widgetDefinition.allowedContent.img.styles.split(/\s*,\s*/);
+          for (var i = 0; i < imgStyles.length; i++) {
+            allowedContentDefinition.styles[imgStyles[i].trim()] = '';
+          }
+        }
+        widgetDefinition.allowedContent = new CKEDITOR.style(allowedContentDefinition);
 
         // Override the 'link' part, to completely disable image2's link
         // support: http://dev.ckeditor.com/ticket/11341.
diff --git a/core/modules/ckeditor/js/plugins/drupalimagecaption/plugin.js b/core/modules/ckeditor/js/plugins/drupalimagecaption/plugin.js
index 94c5353..0963c04 100644
--- a/core/modules/ckeditor/js/plugins/drupalimagecaption/plugin.js
+++ b/core/modules/ckeditor/js/plugins/drupalimagecaption/plugin.js
@@ -55,7 +55,10 @@
         requiredContent.attributes['data-align'] = '';
         requiredContent.attributes['data-caption'] = '';
         widgetDefinition.requiredContent = new CKEDITOR.style(requiredContent);
-        widgetDefinition.allowedContent.img.attributes += ',!data-align,!data-caption';
+        var allowedContent = widgetDefinition.allowedContent.getDefinition();
+        allowedContent.attributes['!data-align'] = '';
+        allowedContent.attributes['!data-caption'] = '';
+        widgetDefinition.allowedContent = new CKEDITOR.style(allowedContent);
 
         // Override allowedContent setting for the 'caption' nested editable.
         // This must match what caption_filter enforces.
diff --git a/core/modules/ckeditor/js/plugins/drupallink/plugin.js b/core/modules/ckeditor/js/plugins/drupallink/plugin.js
index f4db09e..379848e 100644
--- a/core/modules/ckeditor/js/plugins/drupallink/plugin.js
+++ b/core/modules/ckeditor/js/plugins/drupallink/plugin.js
@@ -13,11 +13,13 @@
     init: function (editor) {
       // Add the commands for link and unlink.
       editor.addCommand('drupallink', {
-        allowedContent: {
-          a: {
-            attributes: '!href,target'
+        allowedContent: new CKEDITOR.style({
+          element: 'a',
+          attributes: {
+            '!href': '',
+            'target': ''
           }
-        },
+        }),
         requiredContent: new CKEDITOR.style({
           element: 'a',
           attributes: {