The WinHTTP API cannot obtain content from a website that contains special characters in Windows 7 or in Windows Server 2008 R2

On a computer that is running Windows 7 or Windows Server 2008 R2, you use the WinHTTP API to try to obtain content from a website. This website contains non-RFC compliant characters. In this situation, the WinHTTP API cannot obtain the website content.

For example, you use the WinHttpSendRequest function or the WinHttpReceiveResponse�function to request access to a web resource. This web resource contains a semicolon (;) character in the content. In this case, you may receive an error message that resembles the following:Note This issue does not occur in other versions of Windows that are earlier than Windows 7 and Windows Server 2008 R2.

This issue occurs because of a design change in the Winhttp.dll module in Windows 7 and in Windows Server 2008 R2. The Webio.dll module and the Winhttp.dll have more strict requirements that do not allow HTTP headers to contain non-RFC compliant characters.

Important�After you install this hotfix, a new WINHTTP_OPTION_UNSAFE_HEADER_PARSING�HTTP flag is introduced. To request access to a web resource, you must call the�WinHttpSetOption function to enable this new flag before you call the WinHttpSendRequest function or the � WinHttpReceiveResponse.

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 the problem described in this article. 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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

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 The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

There are no prerequisites to apply this hotfix.

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 7 and Windows Server 2008 R2 file information notes

Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The MANIFEST files (.manifest) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MANIFEST files and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows 7

For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2

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

For more information about Windows HTTP services (WinHTTP API), visit the following Microsoft website:For more information about the WinHttpSendRequest function and the WinHttpReceiveResponse function, visit the following Microsoft websites: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7

Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2

Additional files for all supported IA-64-based versions of Windows Server 2008 R2