diff --git a/nelmio/cors-bundle/1.5/manifest.json b/nelmio/cors-bundle/1.5/manifest.json
index 7df4a31c..e619bee8 100644
--- a/nelmio/cors-bundle/1.5/manifest.json
+++ b/nelmio/cors-bundle/1.5/manifest.json
@@ -6,7 +6,7 @@
         "config/": "%CONFIG_DIR%/"
     },
     "env": {
-        "CORS_ALLOW_ORIGIN": "^https?://localhost:?[0-9]*$"
+        "CORS_ALLOW_ORIGIN": "^https?://localhost(:[0-9]+)?$"
     },
     "aliases": ["cors"]
 }