A potentially dangerous Request.QueryString value was detected

Last Published: April 25, 2020

Error Message

While using the Locator USA Site Starter application for ASP.NET, the following error occurs:

"A potentially dangerous Request.QueryString value was detected from the client (XML="Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted..."


.NET Framework 1.1 is installed on an application that was developed using .NET 1.0. .NET 1.1 uses a higher security setting by default, so a security message that 1.0 users do not see is visable.

Solution or Workaround

Disable these error messages by lowering the security settings. Set validateRequest=false in the Page directive of the *.aspx page that displayed the error. This will turn off request validation for that page only.
The changes below lower the security set by .NET 1.1.

It is highly recommended that a consultation is made with an IT/MIS department, or other qualified computer systems professional, before proceeding.

The first line should be similar to the following:


<%@ Page language="c#" Codebehind="WebForm1.aspx.cs" AutoEventWireup="false" Inherits="TestWebGUI.WebForm1" validateRequest=false%>


<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="TestWebGUI.WebForm1" validateRequest=false%>

Article ID:000006642

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