diff --git a/eng/pipelines/common/evaluate-default-paths.yml b/eng/pipelines/common/evaluate-default-paths.yml
index 5fb74a3741f41..0e4279a9697b9 100644
--- a/eng/pipelines/common/evaluate-default-paths.yml
+++ b/eng/pipelines/common/evaluate-default-paths.yml
@@ -241,6 +241,7 @@ jobs:
       - src/mono/tools/*
       - src/mono/wasi/*
       - src/mono/wasm/debugger/*
+      - src/mono/wasm/host/*
       - src/mono/wasm/Wasm.Build.Tests/*
       - ${{ parameters._const_paths._wasm_pipelines }}
       - ${{ parameters._const_paths._always_exclude }}
@@ -258,6 +259,7 @@ jobs:
       - eng/testing/workloads-testing.targets
       - src/mono/mono/component/mini-wasm-debugger.c
       - src/mono/wasm/debugger/*
+      - src/mono/wasm/host/*
       - src/mono/wasm/Wasm.Build.Tests/*
       - src/mono/nuget/Microsoft.NET.Runtime*
         src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/*
diff --git a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipeEventDispatcher.cs b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipeEventDispatcher.cs
index 708c5afc1bc70..030560b200214 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipeEventDispatcher.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipeEventDispatcher.cs
@@ -103,8 +103,8 @@ private void CommitDispatchConfiguration()
                 new EventPipeProviderConfiguration(NativeRuntimeEventSource.EventSourceName, (ulong)aggregatedKeywords, (uint)enableLevel, null)
             };
 
-            m_sessionID = EventPipeInternal.Enable(null, EventPipeSerializationFormat.NetTrace, DefaultEventListenerCircularMBSize, providerConfiguration);
-            if (m_sessionID == 0)
+            ulong sessionID = EventPipeInternal.Enable(null, EventPipeSerializationFormat.NetTrace, DefaultEventListenerCircularMBSize, providerConfiguration);
+            if (sessionID == 0)
             {
                 throw new EventSourceException(SR.EventSource_CouldNotEnableEventPipe);
             }
@@ -113,7 +113,7 @@ private void CommitDispatchConfiguration()
             EventPipeSessionInfo sessionInfo;
             unsafe
             {
-                if (!EventPipeInternal.GetSessionInfo(m_sessionID, &sessionInfo))
+                if (!EventPipeInternal.GetSessionInfo(sessionID, &sessionInfo))
                 {
                     Debug.Fail("GetSessionInfo returned false.");
                 }
@@ -124,8 +124,11 @@ private void CommitDispatchConfiguration()
             long syncTimeQPC = sessionInfo.StartTimeStamp;
             long timeQPCFrequency = sessionInfo.TimeStampFrequency;
 
+            Debug.Assert(Volatile.Read(ref m_sessionID) == 0);
+            Volatile.Write(ref m_sessionID, sessionID);
+
             // Start the dispatch task.
-            StartDispatchTask(m_sessionID, syncTimeUtc, syncTimeQPC, timeQPCFrequency);
+            StartDispatchTask(sessionID, syncTimeUtc, syncTimeQPC, timeQPCFrequency);
         }
 
         private void StartDispatchTask(ulong sessionID, DateTime syncTimeUtc, long syncTimeQPC, long timeQPCFrequency)
@@ -147,10 +150,11 @@ private void SetStopDispatchTask()
                 return;
             }
 
-            Debug.Assert(m_sessionID != 0);
+            ulong sessionID = Volatile.Read(ref m_sessionID);
+            Debug.Assert(sessionID != 0);
             m_dispatchTaskCancellationSource.Cancel();
-            EventPipeInternal.SignalSession(m_sessionID);
-            m_sessionID = 0;
+            EventPipeInternal.SignalSession(sessionID);
+            Volatile.Write(ref m_sessionID, 0);
         }
 
         private unsafe void DispatchEventsToEventListeners(ulong sessionID, DateTime syncTimeUtc, long syncTimeQPC, long timeQPCFrequency, Task? previousDispatchTask, CancellationToken token)
@@ -190,12 +194,17 @@ private unsafe void DispatchEventsToEventListeners(ulong sessionID, DateTime syn
                 }
             }
 
-            lock (m_dispatchControlLock)
+            // Wait for SignalSession() to be called before we call disable, otherwise
+            // the SignalSession() call could be on a disabled session.
+            SpinWait sw = default;
+            while (Volatile.Read(ref m_sessionID) == sessionID)
             {
-                // Disable the old session. This can happen asynchronously since we aren't using the old session
-                // anymore. We take the lock to make sure we don't call SignalSession on an invalid session ID.
-                EventPipeInternal.Disable(sessionID);
+                sw.SpinOnce();
             }
+
+            // Disable the old session. This can happen asynchronously since we aren't using the old session
+            // anymore.
+            EventPipeInternal.Disable(sessionID);
         }
 
         /// <summary>
diff --git a/src/mono/wasm/host/BrowserHost.cs b/src/mono/wasm/host/BrowserHost.cs
index adb24f81f88da..cbe160eeb0214 100644
--- a/src/mono/wasm/host/BrowserHost.cs
+++ b/src/mono/wasm/host/BrowserHost.cs
@@ -74,7 +74,7 @@ private async Task RunAsync(ILoggerFactory loggerFactory, CancellationToken toke
                                                debugging: _args.CommonConfig.Debugging);
         runArgsJson.Save(Path.Combine(_args.CommonConfig.AppPath, "runArgs.json"));
 
-        string[] urls = envVars.TryGetValue("ASPNETCORE_URLS", out string? aspnetUrls)
+        string[] urls = (envVars.TryGetValue("ASPNETCORE_URLS", out string? aspnetUrls) && aspnetUrls.Length > 0)
                             ? aspnetUrls.Split(';', StringSplitOptions.RemoveEmptyEntries)
                             : new string[] { $"http://127.0.0.1:{_args.CommonConfig.HostProperties.WebServerPort}", "https://127.0.0.1:0" };
 
diff --git a/src/mono/wasm/host/DevServer/DevServer.cs b/src/mono/wasm/host/DevServer/DevServer.cs
index 1acbe6954eeb3..9a5a079cee695 100644
--- a/src/mono/wasm/host/DevServer/DevServer.cs
+++ b/src/mono/wasm/host/DevServer/DevServer.cs
@@ -46,7 +46,8 @@ internal static class DevServer
                 services.AddSingleton(Options.Create(options));
                 services.AddSingleton(realUrlsAvailableTcs);
                 services.AddRouting();
-            });
+            })
+            .UseUrls(options.Urls);
 
 
         IWebHost? host = builder.Build();
diff --git a/src/mono/wasm/host/RuntimeConfigJson.cs b/src/mono/wasm/host/RuntimeConfigJson.cs
index ed698ed8fb372..3ad30dd88015a 100644
--- a/src/mono/wasm/host/RuntimeConfigJson.cs
+++ b/src/mono/wasm/host/RuntimeConfigJson.cs
@@ -24,7 +24,7 @@ internal sealed record WasmHostProperties(
      int? FirefoxDebuggingPort,
      int? ChromeProxyPort,
      int? ChromeDebuggingPort,
-     int WebServerPort = 9000)
+     int WebServerPort = 0)
 {
     // using an explicit property because the deserializer doesn't like
     // extension data in the record constructor