diff --git a/routes/web.php b/routes/web.php
index 67debfa..c9153ef 100644
--- a/routes/web.php
+++ b/routes/web.php
@@ -14,6 +14,7 @@ Route::get('dl/{media}', function (Media $media, Request $request) {
         $media->file_name
     );
 })
+    ->whereNumber('media')
     ->name('dl')
     ->middleware('signed');
 
@@ -27,6 +28,7 @@ Route::get('media/{media}', function (Media $media, Request $request) {
         ]
     );
 })
+    ->whereNumber('media')
     ->name('media.signed')
     ->middleware('signed');
 
diff --git a/tests/Feature/MediaRouteTest.php b/tests/Feature/MediaRouteTest.php
new file mode 100644
index 0000000..0fc191c
--- /dev/null
+++ b/tests/Feature/MediaRouteTest.php
@@ -0,0 +1,11 @@
+<?php
+
+it('returns 404 for non-numeric media id', function (string $invalidId) {
+    $this->get("/media/{$invalidId}")
+        ->assertNotFound();
+})->with(['*', 'abc', 'foo-bar']);
+
+it('returns 404 for non-numeric dl id', function (string $invalidId) {
+    $this->get("/dl/{$invalidId}")
+        ->assertNotFound();
+})->with(['*', 'abc', 'foo-bar']);