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FIX: Forms authentication cookies compatibility issue between .NET Framework 1.1 and .NET Framework 2.0 SP2 ASP.NET applications after you apply the security update from security bulletin MS10-070

Consider the following scenario:
  • You have multiple applications that are run on different versions of the Microsoft .NET Framework.
  • You use forms authentication in these applications.
  • You configure the applications to share the same authentication cookie for seamless browsing between the applications.
  • You apply the security update that is mentioned in security bulletin MS10-070.
In this scenario, the .NET Framework 2.0 SP2 ASP.NET applications cannot use forms authentication cookies that were issued by the .NET Framework 1.1 ASP.NET applications, and vice-versa.


Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

To download this hotfix from the MSDN Code Gallery, visit the following Microsoft website:

Note The MSDN Code Gallery displays the languages for which the hotfix is available. If you do not see your language listed, it is because the Code Gallery resource page is not available for that language.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:

Note To download this hotfix, you can also visit the following Microsoft website:


 To apply this hotfix, you must have the Microsoft .NET Framework 1.1 Service Pack 1 installed.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

Installation information

Two hotfix packages are provided for this problem. Download and apply the appropriate hotfix for the operating system that your computer is running.
  • If your computer is running an x86-based version of Windows Server 2003, download and install the WindowsServer2003-KB2433751-x86-ENU.exe hotfix package.
  • If your computer is running an x64-based version of Windows Server 2003 or an IA-64-based version of Windows Server 2003, download and install the NDP1.1sp1-KB2433751-X86.exe hotfix package.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

For all supported x86-based versions of the .NET Framework 1.1 Service Pack 1
File nameFile versionFile sizeDateTimePlatform
Mscorlib.ldoNot applicable10,95212-Oct-201018:53Not applicable
System.ldoNot applicable11,54012-Oct-201019:55Not applicable
For all supported x86-based versions of Windows Server 2003 that have the .NET Framework 1.1 Service Pack 1 installed
File nameFile versionFile sizeDateTimePlatformSP requirement

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the forms authentication across applications, visit the following Microsoft website:For more information about the forms authentication ticket and cookie, click the following article number to view the article in the Microsoft Knowledge Base:
910443 Understanding the Forms Authentication Ticket and Cookie

Article ID: 2433751 - Last Review: 10/29/2010 22:54:00 - Revision: 2.0

  • Microsoft .NET Framework 1.1 Service Pack 1
  • kbqfe kbfix kbhotfixserver kbexpertiseadvanced kbsurveynew atdownload KB2433751