diff --git a/plugins/libs/plugins-runtime/src/lib/api/index.ts b/plugins/libs/plugins-runtime/src/lib/api/index.ts
index 6d452d2ddc..b24c2328f3 100644
--- a/plugins/libs/plugins-runtime/src/lib/api/index.ts
+++ b/plugins/libs/plugins-runtime/src/lib/api/index.ts
@@ -68,8 +68,21 @@ export function createApi(
       },
 
       sendMessage(message: unknown) {
+        let cloneableMessage: unknown;
+
+        try {
+          cloneableMessage = structuredClone(message);
+        } catch (err) {
+          console.error(
+            'plugin sendMessage: the message could not be cloned. ' +
+              'Ensure the message does not contain functions, DOM nodes, or other non-serializable values.',
+            err,
+          );
+          return;
+        }
+
         const event = new CustomEvent('message', {
-          detail: message,
+          detail: cloneableMessage,
         });
 
         plugin.getModal()?.dispatchEvent(event);
diff --git a/plugins/libs/plugins-runtime/src/lib/modal/plugin-modal.ts b/plugins/libs/plugins-runtime/src/lib/modal/plugin-modal.ts
index b9a9183c8b..3346175212 100644
--- a/plugins/libs/plugins-runtime/src/lib/modal/plugin-modal.ts
+++ b/plugins/libs/plugins-runtime/src/lib/modal/plugin-modal.ts
@@ -129,7 +129,14 @@ export class PluginModalElement extends HTMLElement {
         return;
       }
 
-      iframe.contentWindow.postMessage((e as CustomEvent).detail, '*');
+      try {
+        iframe.contentWindow.postMessage((e as CustomEvent).detail, '*');
+      } catch (err) {
+        console.error(
+          'plugin modal: failed to send message to iframe via postMessage.',
+          err,
+        );
+      }
     });
 
     this.shadowRoot.appendChild(this.wrapper);