diff --git a/cdk/lib/constructs/cf-lambda-furl-service/service.ts b/cdk/lib/constructs/cf-lambda-furl-service/service.ts
index 39fc7ae..d3d1811 100644
--- a/cdk/lib/constructs/cf-lambda-furl-service/service.ts
+++ b/cdk/lib/constructs/cf-lambda-furl-service/service.ts
@@ -89,6 +89,13 @@ export class CloudFrontLambdaFunctionUrlService extends Construct {
         'X-HTTP-Method-Override',
         'X-HTTP-Method',
         'X-Method-Override',
+        // Next.js App Router RSC headers to prevent cache poisoning.
+        // Without these, RSC flight responses (text/x-component) and HTML responses
+        // share the same cache key, causing wrong content to be served.
+        'RSC',
+        'Next-Router-Prefetch',
+        'Next-Router-State-Tree',
+        'Next-URL',
       ),
       defaultTtl: Duration.seconds(0),
       cookieBehavior: CacheCookieBehavior.all(),
diff --git a/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit-without-domain.test.ts.snap b/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit-without-domain.test.ts.snap
index c3bca2c..1088908 100644
--- a/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit-without-domain.test.ts.snap
+++ b/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit-without-domain.test.ts.snap
@@ -4094,6 +4094,10 @@ service iptables save",
                 "X-HTTP-Method-Override",
                 "X-HTTP-Method",
                 "X-Method-Override",
+                "RSC",
+                "Next-Router-Prefetch",
+                "Next-Router-State-Tree",
+                "Next-URL",
               ],
             },
             "QueryStringsConfig": {
diff --git a/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit.test.ts.snap b/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit.test.ts.snap
index 520dfb6..c83e243 100644
--- a/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit.test.ts.snap
+++ b/cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit.test.ts.snap
@@ -3918,6 +3918,10 @@ service iptables save",
                 "X-HTTP-Method-Override",
                 "X-HTTP-Method",
                 "X-Method-Override",
+                "RSC",
+                "Next-Router-Prefetch",
+                "Next-Router-State-Tree",
+                "Next-URL",
               ],
             },
             "QueryStringsConfig": {