diff --git a/voicevox_engine/app/middlewares.py b/voicevox_engine/app/middlewares.py
index 3c44a2125..14fd9e1f2 100644
--- a/voicevox_engine/app/middlewares.py
+++ b/voicevox_engine/app/middlewares.py
@@ -28,7 +28,9 @@ async def global_execution_handler(request: Request, exc: Exception) -> Response
     app.add_middleware(ServerErrorMiddleware, handler=global_execution_handler)
 
     # CORS用のヘッダを生成するミドルウェア
-    localhost_regex = "^https?://(localhost|127\\.0\\.0\\.1|\\[::1\\])(:[0-9]+)?$"
+    localhost_regex = (
+        r"^[a-zA-Z+\-\.]+://(([^/]+\.)localhost|127\.0\.0\.1|\[::1\])(:[0-9]+)?$"
+    )
     compiled_localhost_regex = re.compile(localhost_regex)
     allowed_origins = ["*"]
     if cors_policy_mode == "localapps":