title: A potentially dangerous Request.Form value was detected from the client (wresult="<trust:RequestSecuri...")
body: <p>I am also getting a request validation error when using WIF.  I get correctly sent to the STS, but on the way back, I get this validation error.</p>
  
  <p>I followed all the instructions.  </p>
  
  <pre><code>&lt;httpRuntime  requestValidationMode="2.0" /&gt;
  </code></pre>
  
  <p>check!</p>
  
  <pre><code>    [ValidateInput(false)]
  </code></pre>
  
  <p>check!</p>
  
  <pre><code>&lt;pages validateRequest="false" &gt;
  </code></pre>
  
  <p>check!</p>
  
  <p>I tried a custom validator, but it never gets instantiated.  </p>
  
  <p>Error stack:</p>
  
  <pre><code>[HttpRequestValidationException (0x80004005): A potentially dangerous Request.Form value was detected from the client (wresult="trust:RequestSecuri...").]
     System.Web.HttpRequest.ValidateString(String value, String collectionKey, RequestValidationSource requestCollection) +11396740
     System.Web.HttpRequest.ValidateNameValueCollection(NameValueCollection nvc, RequestValidationSource requestCollection) +82
     System.Web.HttpRequest.get_Form() +212
     Microsoft.IdentityModel.Web.WSFederationAuthenticationModule.IsSignInResponse(HttpRequest request) +26
     Microsoft.IdentityModel.Web.WSFederationAuthenticationModule.CanReadSignInResponse(HttpRequest request, Boolean onPage) +145
     Microsoft.IdentityModel.Web.WSFederationAuthenticationModule.OnAuthenticateRequest(Object sender, EventArgs args) +108
     System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +80
     System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously) +270
  </code></pre>
  
  <p>Any suggestions? </p>