diff --git a/addons/web_editor/static/src/js/editor/snippets.options.js b/addons/web_editor/static/src/js/editor/snippets.options.js
index 54df499c5b0..26c19a6367c 100644
--- a/addons/web_editor/static/src/js/editor/snippets.options.js
+++ b/addons/web_editor/static/src/js/editor/snippets.options.js
@@ -7127,6 +7127,11 @@ registry.BackgroundShape = SnippetOptionWidget.extend({
             this._lastShapePalette = palette;
             this._shapeBackgroundImagePerClass = {};
             for (const styleSheet of this.$target[0].ownerDocument.styleSheets) {
+                if (styleSheet.href && new URL(styleSheet.href).host !== location.host) {
+                    // In some browsers, if a stylesheet is loaded from a different domain
+                    // accessing cssRules results in a SecurityError.
+                    continue;
+                }
                 for (const rule of [...styleSheet.cssRules]) {
                     if (rule.selectorText && rule.selectorText.startsWith(".o_we_shape.")) {
                         this._shapeBackgroundImagePerClass[rule.selectorText] = rule.style.backgroundImage;