diff --git a/axum-extra/src/protobuf.rs b/axum-extra/src/protobuf.rs
index ddf45671..906ab5f3 100644
--- a/axum-extra/src/protobuf.rs
+++ b/axum-extra/src/protobuf.rs
@@ -188,6 +188,7 @@ impl IntoResponse for ProtoBufDecodeError {
 /// Contains one variant for each way the [`ProtoBuf`] extractor
 /// can fail.
 #[derive(Debug)]
+#[non_exhaustive]
 pub enum ProtoBufRejection {
     #[allow(missing_docs)]
     ProtoBufDecodeError(ProtoBufDecodeError),