diff --git a/packages/frameworks-express/src/index.ts b/packages/frameworks-express/src/index.ts
index 95c72c28cd..ee7a109e8c 100644
--- a/packages/frameworks-express/src/index.ts
+++ b/packages/frameworks-express/src/index.ts
@@ -206,5 +206,6 @@ export async function getSession(
 }
 
 function getBasePath(req: e.Request) {
-  return req.baseUrl.split(req.params[0])[0].replace(/\/$/, "")
+  const params = req.params.splat ?? req.params[0];
+  return req.baseUrl.split(params)[0].replace(/\/$/, "")
 }