From 8981ab5955307fbbece2bbacdbff66ebf08c4c45 Mon Sep 17 00:00:00 2001
From: Rico Suter <mail@rsuter.com>
Date: Tue, 17 Feb 2026 06:30:05 +0100
Subject: [PATCH] Fix TcpTransportListener resource leak in
 ServerBase.StopAsync (#3561)
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ServerBase.StopAsync() calls Close() on each transport listener then
Clear() on the list. ServerBase.Dispose() later iterates
TransportListeners to call Dispose() on each — but the list is already
empty, so TcpTransportListener.Dispose() never runs.

Add Utils.SilentDispose() after Close() in StopAsync to ensure
TcpTransportListener.Dispose() executes before the list is cleared.
---
 Stack/Opc.Ua.Core/Stack/Server/ServerBase.cs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Stack/Opc.Ua.Core/Stack/Server/ServerBase.cs b/Stack/Opc.Ua.Core/Stack/Server/ServerBase.cs
index db6ed17f33..7ac6350fb8 100644
--- a/Stack/Opc.Ua.Core/Stack/Server/ServerBase.cs
+++ b/Stack/Opc.Ua.Core/Stack/Server/ServerBase.cs
@@ -554,7 +554,7 @@ namespace Opc.Ua
                 ServerError = new ServiceResult(e);
             }
 
-            // close any listeners.
+            // close and dispose any listeners.
             List<ITransportListener> listeners = TransportListeners;
 
             if (listeners != null)
@@ -572,6 +572,8 @@ namespace Opc.Ua
                             "Unexpected error closing a listener {Name}.",
                             listeners[ii].GetType().FullName);
                     }
+
+                    Utils.SilentDispose(listeners[ii]);
                 }
 
                 listeners.Clear();