diff --git a/src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/ManagedWebSocket.cs b/src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/ManagedWebSocket.cs
index 971c2ceff82be4..01800a7a401330 100644
--- a/src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/ManagedWebSocket.cs
+++ b/src/libraries/System.Net.WebSockets/src/System/Net/WebSockets/ManagedWebSocket.cs
@@ -26,8 +26,6 @@ namespace System.Net.WebSockets
     /// </remarks>
     internal sealed partial class ManagedWebSocket : WebSocket
     {
-        /// <summary>Thread-safe random number generator used to generate masks for each send.</summary>
-        private static readonly RandomNumberGenerator s_random = RandomNumberGenerator.Create();
         /// <summary>Encoding for the payload of text messages: UTF8 encoding that throws if invalid bytes are discovered, per the RFC.</summary>
         private static readonly UTF8Encoding s_textEncoding = new UTF8Encoding(encoderShouldEmitUTF8Identifier: false, throwOnInvalidBytes: true);
 
@@ -63,8 +61,6 @@ internal sealed partial class ManagedWebSocket : WebSocket
         private readonly string? _subprotocol;
         /// <summary>Timer used to send periodic pings to the server, at the interval specified</summary>
         private readonly Timer? _keepAliveTimer;
-        /// <summary>CancellationTokenSource used to abort all current and future operations when anything is canceled or any error occurs.</summary>
-        private readonly CancellationTokenSource _abortSource = new CancellationTokenSource();
         /// <summary>Buffer used for reading data from the network.</summary>
         private readonly Memory<byte> _receiveBuffer;
         /// <summary>
@@ -136,7 +132,7 @@ internal sealed partial class ManagedWebSocket : WebSocket
         private Task _lastReceiveAsync = Task.CompletedTask;
 
         /// <summary>Lock used to protect update and check-and-update operations on _state.</summary>
-        private object StateUpdateLock => _abortSource;
+        private object StateUpdateLock => _sendFrameAsyncLock;
         /// <summary>
         /// We need to coordinate between receives and close operations happening concurrently, as a ReceiveAsync may
         /// be pending while a Close{Output}Async is issued, which itself needs to loop until a close frame is received.
@@ -173,25 +169,6 @@ internal ManagedWebSocket(Stream stream, bool isServer, string? subprotocol, Tim
             const int ReceiveBufferMinLength = MaxControlPayloadLength;
             _receiveBuffer = new byte[ReceiveBufferMinLength];
 
-            // Set up the abort source so that if it's triggered, we transition the instance appropriately.
-            // There's no need to store the resulting CancellationTokenRegistration, as this instance owns
-            // the CancellationTokenSource, and the lifetime of that CTS matches the lifetime of the registration.
-            _abortSource.Token.UnsafeRegister(static s =>
-            {
-                var thisRef = (ManagedWebSocket)s!;
-
-                lock (thisRef.StateUpdateLock)
-                {
-                    WebSocketState state = thisRef._state;
-                    if (state != WebSocketState.Closed && state != WebSocketState.Aborted)
-                    {
-                        thisRef._state = state != WebSocketState.None && state != WebSocketState.Connecting ?
-                            WebSocketState.Aborted :
-                            WebSocketState.Closed;
-                    }
-                }
-            }, this);
-
             // Now that we're opened, initiate the keep alive timer to send periodic pings.
             // We use a weak reference from the timer to the web socket to avoid a cycle
             // that could keep the web socket rooted in erroneous cases.
@@ -387,10 +364,24 @@ private async Task CloseOutputAsyncCore(WebSocketCloseStatus closeStatus, string
 
         public override void Abort()
         {
-            _abortSource.Cancel();
+            OnAborted();
             Dispose(); // forcibly tear down connection
         }
 
+        private void OnAborted()
+        {
+            lock (StateUpdateLock)
+            {
+                WebSocketState state = _state;
+                if (state != WebSocketState.Closed && state != WebSocketState.Aborted)
+                {
+                    _state = state != WebSocketState.None && state != WebSocketState.Connecting ?
+                        WebSocketState.Aborted :
+                        WebSocketState.Closed;
+                }
+            }
+        }
+
         public override ValueTask SendAsync(ReadOnlyMemory<byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken cancellationToken)
         {
             return SendPrivateAsync(buffer, messageType, endOfMessage ? WebSocketMessageFlags.EndOfMessage : default, cancellationToken);
@@ -721,7 +712,7 @@ private static int WriteHeader(MessageOpcode opcode, byte[] sendBuffer, ReadOnly
         /// <param name="buffer">The buffer to which to write the mask.</param>
         /// <param name="offset">The offset into the buffer at which to write the mask.</param>
         private static void WriteRandomMask(byte[] buffer, int offset) =>
-            s_random.GetBytes(buffer, offset, MaskLength);
+            RandomNumberGenerator.Fill(buffer.AsSpan(offset, MaskLength));
 
         /// <summary>
         /// Receive the next text, binary, continuation, or close message, returning information about it and
@@ -917,7 +908,7 @@ private async ValueTask<TResult> ReceiveAsyncPrivate<TResult>(Memory<byte> paylo
                 {
                     throw new OperationCanceledException(nameof(WebSocketState.Aborted), exc);
                 }
-                _abortSource.Cancel();
+                OnAborted();
 
                 if (exc is WebSocketException)
                 {