diff --git a/addons/website_event_track/controllers/webmanifest.py b/addons/website_event_track/controllers/webmanifest.py
index 9f4967ed70d..627c2581577 100644
--- a/addons/website_event_track/controllers/webmanifest.py
+++ b/addons/website_event_track/controllers/webmanifest.py
@@ -48,8 +48,13 @@ class TrackManifest(http.Controller):
         """ Returns a ServiceWorker javascript file scoped for website_event
         """
         sw_file = get_module_resource('website_event_track', 'static/src/js/service_worker.js')
-        with open(sw_file, 'rb') as fp:
+        with open(sw_file, 'r') as fp:
             body = fp.read()
+        js_cdn_url = 'undefined'
+        if request.website.cdn_activated:
+            cdn_url = request.website.cdn_url.replace('"','%22').replace('\x5c','%5C')
+            js_cdn_url = '"%s"' % cdn_url
+        body = body.replace('__ODOO_CDN_URL__', js_cdn_url)
         response = request.make_response(body, [
             ('Content-Type', 'text/javascript'),
             ('Service-Worker-Allowed', url_for('/event')),
diff --git a/addons/website_event_track/static/src/js/service_worker.js b/addons/website_event_track/static/src/js/service_worker.js
index c6b6800aacf..41ce7e54297 100644
--- a/addons/website_event_track/static/src/js/service_worker.js
+++ b/addons/website_event_track/static/src/js/service_worker.js
@@ -5,6 +5,7 @@ const SYNCABLE_ROUTES = ["/event/track/toggle_reminder"];
 const CACHABLE_ROUTES = ["/web/webclient/version_info"];
 const MAX_CACHE_SIZE = 512 * 1024 * 1024; // 500 MB
 const MAX_CACHE_QUOTA = 0.5;
+const CDN_URL = __ODOO_CDN_URL__; // {string|undefined} the cdn_url configured for the website if activated
 
 const { Store, set, get, del } = idbKeyval;
 const pendingRequestsQueueName = `${PREFIX}-pending-requests`;
@@ -12,6 +13,8 @@ const cacheName = `${PREFIX}-cache`;
 const syncStore = new Store(`${PREFIX}-sync-db`, `${PREFIX}-sync-store`);
 const cacheStore = new Store(`${PREFIX}-cache-db`, `${PREFIX}-cache-store`);
 const offlineRoute = `${self.registration.scope}/offline`;
+const scopeURL = new URL(self.registration.scope);
+const cdnURL = CDN_URL ? (CDN_URL.startsWith("http") ? new URL(CDN_URL) : new URL(`http:${CDN_URL}`)) : undefined;
 
 /**
  *
@@ -147,6 +150,13 @@ const buildEmptyResponse = () => new Response(JSON.stringify({ jsonrpc: "2.0", i
  * @returns {Promise}
  */
 const cacheRequest = async (request, response) => {
+    // only attempts to cache local or cdn delivered urls
+    const url = new URL(request.url);
+    if (url.hostname !== scopeURL.hostname && (!cdnURL || url.hostname !== cdnURL.hostname)) {
+        console.error(`ignoring cache for ${request.url} => ${url.hostname}, local: ${scopeURL.hostname}, cdn: ${cdnURL ? cdnURL.hostname : cdnURL}`);
+        return;
+    }
+
     // don't even attempt to cache:
     //  - error pages (why cache that?)
     //  - non-"basic" response types, which include tracker 1-time opaque requests