diff --git a/packages/backend/src/server/web/ClientServerService.ts b/packages/backend/src/server/web/ClientServerService.ts
index 8dcd76ee71..54c608ac9e 100644
--- a/packages/backend/src/server/web/ClientServerService.ts
+++ b/packages/backend/src/server/web/ClientServerService.ts
@@ -503,6 +503,7 @@ export class ClientServerService {
 
 		// ServiceWorker
 		fastify.get('/sw.js', async (request, reply) => {
+			reply.header('content-security-policy', `default-src \'self'; connect-src \'self\'${ this.config.mediaProxy ? ` ${new URL(this.config.mediaProxy).origin}` : '' }`);
 			return await reply.sendFile('/sw.js', swAssets, {
 				maxAge: ms('10 minutes'),
 			});