diff --git a/packages/custom_lint/CHANGELOG.md b/packages/custom_lint/CHANGELOG.md
index e414b7c9..9263c47e 100644
--- a/packages/custom_lint/CHANGELOG.md
+++ b/packages/custom_lint/CHANGELOG.md
@@ -4,6 +4,7 @@
 - Fix watch mode not quitting with `q` (thanks to @kuhnroyal)
 - Improve the command line's output (thanks to @kuhnroyal)
 - Update uuid to 4.0.0
+- Fixed a port leak
 
 ## 0.5.3 - 2023-08-29
 
diff --git a/packages/custom_lint/lib/src/v2/server_to_client_channel.dart b/packages/custom_lint/lib/src/v2/server_to_client_channel.dart
index 47acdfdf..ccda5479 100644
--- a/packages/custom_lint/lib/src/v2/server_to_client_channel.dart
+++ b/packages/custom_lint/lib/src/v2/server_to_client_channel.dart
@@ -15,7 +15,11 @@ import 'protocol.dart';
 
 Future<int> _findPossiblyUnusedPort() {
   return SocketCustomLintServerToClientChannel._createServerSocket()
-      .then((value) => value.port);
+      .then((value) {
+    final port = value.port;
+    value.close();
+    return port;
+  });
 }
 
 Future<T> _asyncRetry<T>(