Microsoft · Security update · April 13, 2021

KB5001339: April 2021 cumulative update for Windows 10 1803

KB5001339, released April 13, 2021, fixes 70 CVEs across 3 products. One of them is being exploited (CVE-2021-28310); 1 on CISA KEV. Patch Radar priority: Patch now. The product is no longer supported.

Patch now1 on CISA KEV1 publicly disclosedUnsupported product

CVEs closed

14 rated Critical

Exploited

CVE-2021-28310

Exploitation more likely

Microsoft's assessment

Highest EPSS

0.6410

99th percentile

Priority of the 70 CVEs

Patch now 1
                                Urgent 18
                                High 32
                                Routine 19

Applies to

Product	Build after install
Windows 10 Version 1803 for 32-bit Systems	17134.2145
Windows 10 Version 1803 for ARM64-based Systems	17134.2145
Windows 10 Version 1803 for x64-based Systems	17134.2145

CVEs this fix closes

Priority	CVE	Component	Impact	CVSS	EPSS	Exploitation
Patch now	CVE-2021-28310	Windows Win32K	Elevation of Privilege	7.8	0.0840	KEVExploited
Urgent	CVE-2021-28325	Windows SMB Server	Information Disclosure	6.5	0.6410	More likely
Urgent	CVE-2021-28319	Windows TCP/IP	Denial of Service	7.5	0.0999	More likely
Urgent	CVE-2021-28442	Windows TCP/IP	Information Disclosure	6.5	0.0693	More likely
Urgent	CVE-2021-27095	Windows Media Player	Remote Code Execution	7.8	0.0435	Exploitation Less Likely
Urgent	CVE-2021-28333	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0254	Exploitation Less Likely
Urgent	CVE-2021-28329	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28330	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28331	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28332	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28334	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28335	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28336	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28337	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28338	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28339	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28343	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0247	Exploitation Less Likely
Urgent	CVE-2021-28315	Windows Media Player	Remote Code Execution	7.8	0.0160	Exploitation Less Likely
Urgent	CVE-2021-27072	Windows Win32K	Elevation of Privilege	7.0	0.0065	More likely
High	CVE-2021-28439	Windows TCP/IP	Denial of Service	7.5	0.0653	Exploitation Less Likely
High	CVE-2021-26415	Windows Installer	Elevation of Privilege	7.8	0.0357	Exploitation Less Likely
High	CVE-2021-28327	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0254	Exploitation Less Likely
High	CVE-2021-28340	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0254	Exploitation Less Likely
High	CVE-2021-28344	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0254	Exploitation Less Likely
High	CVE-2021-28356	Windows Remote Procedure Call Runtime	Remote Code Execution	8.8	0.0254	Exploitation Less Likely

Released the same day

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Microsoft Office 2010 Service Pack 2 (32-bit editions), Microsoft Office 2010 Service Pack 2 (64-bit editions)
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Microsoft Excel 2010 Service Pack 2 (32-bit editions), Microsoft Excel 2010 Service Pack 2 (64-bit editions)
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Microsoft Office 2013 Service Pack 1 (32-bit editions), Microsoft Office 2013 Service Pack 1 (64-bit editions)
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Microsoft Office 2013 Service Pack 1 (32-bit editions), Microsoft Office 2013 Service Pack 1 (64-bit editions)
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Microsoft SharePoint Enterprise Server 2013 Service Pack 1
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Microsoft Outlook 2010 Service Pack 2 (32-bit editions), Microsoft Outlook 2010 Service Pack 2 (64-bit editions)
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Microsoft Word 2016 (32-bit edition), Microsoft Word 2016 (64-bit edition)
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Microsoft SharePoint Enterprise Server 2013 Service Pack 1
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Microsoft Word 2013 RT Service Pack 1, Microsoft Word 2013 Service Pack 1 (32-bit editions), Microsoft Word 2013 Service Pack 1 (64-bit editions)
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Microsoft Office 2010 Service Pack 2 (32-bit editions), Microsoft Office 2010 Service Pack 2 (64-bit editions)
KB4493218
Microsoft Word 2010 Service Pack 2 (32-bit editions), Microsoft Word 2010 Service Pack 2 (64-bit editions)

Vendor advisory

https://support.microsoft.com/help/5001339

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