diff --git a/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml b/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml
index 181429f220ea5..321a5fdd76089 100644
--- a/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml
+++ b/packages/aws-cdk/lib/api/bootstrap/bootstrap-template.yaml
@@ -182,6 +182,7 @@ Resources:
           - HasCustomFileAssetsBucketName
           - Fn::Sub: "${FileAssetsBucketName}"
           - Fn::Sub: cdk-${Qualifier}-assets-${AWS::AccountId}-${AWS::Region}
+      AccessControl: Private
       BucketEncryption:
         ServerSideEncryptionConfiguration:
           - ServerSideEncryptionByDefault: