diff --git a/stapler/handlers.py b/stapler/handlers.py
index b9ece97..f00de8a 100644
--- a/stapler/handlers.py
+++ b/stapler/handlers.py
@@ -73,6 +73,10 @@ class BaseHandler(abc.ABC, http.server.BaseHTTPRequestHandler):
         else:
             self.send_status_only(code, message)
 
+    @typing.override
+    def address_string(self) -> str:  # pragma: no cover
+        return re.sub(r"[^\x00-\x7F]+", "", super().address_string())
+
     @typing.override
     def log_message(self, format: str, *args: typing.Any) -> None:  # pragma: no cover
         fmt = "%s - " + format
diff --git a/tests/test_handlers.py b/tests/test_handlers.py
index 2c6611f..b7596ce 100644
--- a/tests/test_handlers.py
+++ b/tests/test_handlers.py
@@ -1268,6 +1268,7 @@ class TestUpgradeHandler(BaseHandlerTestCase):
             handler.headers = collections.defaultdict(lambda: None, headers)  # ty:ignore[invalid-assignment]
             handler.rfile = rfile if rfile is not None else io.BytesIO()
             handler.wfile = io.BytesIO()
+            handler.client_address = ("127.0.0.1", 12345)
             handler.logger = unittest.mock.Mock(logging.Logger)
             handler.data_dir = self.data_dir
             return handler