diff --git a/src/SignalR/server/Core/src/HubConnectionContext.cs b/src/SignalR/server/Core/src/HubConnectionContext.cs
index fff578ff06..f5f870b38b 100644
--- a/src/SignalR/server/Core/src/HubConnectionContext.cs
+++ b/src/SignalR/server/Core/src/HubConnectionContext.cs
@@ -396,7 +396,7 @@ namespace Microsoft.AspNetCore.SignalR
                 var input = Input;
 
                 using (var cts = new CancellationTokenSource())
-                using (var registration = cts.Token.Register(_cancelReader, input))
+                using (var registration = cts.Token.UnsafeRegister(_cancelReader, input))
                 {
                     if (!Debugger.IsAttached)
                     {