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This security update resolves a vulnerability in Microsoft .NET Framework that could allow remote code execution when .NET Framework processes untrusted input. An attacker who successfully exploits this vulnerability in software by using .NET Framework could take control of an affected system. The attacker could then install programs; view, change, or delete data; or create new accounts that have full user rights. Users whose accounts are configured to have fewer user rights on the system could be less affected than users who operate with administrative user rights.
To exploit the vulnerability, an attacker would first have to convince the user to open a malicious document or application.
This security update addresses the vulnerability by correcting how .NET Framework validates untrusted input.
To learn more about this vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2018-8421.
Important If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.
For more information about this security update as it relates to Windows Server 2012, see the following article in the Microsoft Knowledge Base:
4457919 Security and Quality Rollup updates for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 for Windows Server 2012 (KB 4457919)
After the September 2018 .NET Framework security update is applied to resolve CVE-2018-8421 (.NET Framework remote code execution vulnerability), SharePoint out-of-the-box workflows stop working.
For more information about this known issue, see the following article in the Microsoft Knowledge Base:
4465015 SharePoint Workflows stop working after you install .NET security updates for CVE-2018-8421
This update is available through Windows Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.
On your WSUS server, follow these steps:
The updates are now available for installation through WSUS.
For deployment details for this security update, go to the following article in the Microsoft Knowledge Base:
20180911 Security update deployment information: September 11, 2018
Note We do not recommend that you remove any security update. To remove this update, use the Programs and Features item in Control Panel.
This update does not require a system restart after you apply it unless files that are being updated are locked or are being used.
This update replaces previously released updates KB 4345591 and KB 4346081.
| File name | SHA1 hash | SHA256 hash |
|---|---|---|
| Windows8-RT-KB4457042-x64.msu | 3624D9B9B32E2D39359F297777344D98D8A3DA39 | A73358BBBCF7D37187B9D9C3FB2814C4276E6DFD42D105153F41371EACC9038A |
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