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Affichage des articles du juillet, 2016

ASP-NET: The URL-encoded form data is not valid

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In ASP.NET 4.x, there is an upper bound on the number of simultaneous HTTP form elements that may be posted. The default is 1000 without explicitly changing it with this key in the <appSettings> portion of the web.config: <configuration>   <appSettings>     <add key="aspnet:MaxHttpCollectionKeys"     value="2000" />   </appSettings> </configuration> This patch was released by Microsoft in 2011 to prevent a Denial of Service vulnerability that involved an attacker overwhelming a request with too many keys (the science of which is beyond the remit of this question). Here is the official statement from Microsoft: This security update resolves one publicly disclosed vulnerability and three privately reported vulnerabilities in Microsoft .NET Framework.  The most severe of these vulnerabilities could allow elevation of privilege if an unauthenticated attacker sends a specially crafted web request to the target site.