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Article ID: 927579 - Last Review: October 8, 2011 - Revision: 2.0

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In the Microsoft .NET Framework 2.0, the InitializeSecurityContext function requires two input buffers if the InitializeSecurityContext function is called more than one time. However, the System.Net.Security.SslStream class calls the InitializeSecurityContext function incorrectly. The System.Net.Security.SslStream class always calls the InitializeSecurityContext function by using only one input buffer.


Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next .NET Framework 2.0 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site: (
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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 that are installed on the computer.

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.
The .NET Framework 2.0, x86-based versions
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File nameFile versionFile sizeDateTimePlatform
The .NET Framework 2.0, x64-based versions
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File nameFile versionFile sizeDateTimePlatform
The .NET Framework 2.0, Itanium-based versions
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File nameFile versionFile sizeDateTimePlatform


You may experience this problem when you use the InitializeSecurityContext function to implement a security service provider (SSP). To work around this problem in this case, follow these steps:
  1. Add code that determines whether an additional buffer must be sent to the Security Service Provider Interface (SSPI) caller.
  2. If an additional buffer must be sent, add code that determines whether the SSPI caller sent the additional buffer.
  3. If the SSPI caller did not send the additional buffer, add code that stops the SSP call.


Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.


For more information about the InitializeSecurityContext function, visit the following Microsoft Developer Network (MSDN) Web sites:
InitializeSecurityContext (Schannel) (
Extra buffers returned by Schannel (
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684  ( ) Description of the standard terminology that is used to describe Microsoft software updates

  • Microsoft .NET Framework 2.0
kbqfe KB927579
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