44 flaws fixed through the August 2021 Patch Tuesday release

Vlad Turiceanu
by Vlad Turiceanu
Editor-in-Chief
Passionate about technology, Windows, and everything that has a power button, he spent most of his time developing new skills and learning more about the tech world. Coming from a solid background in PC... Read more
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  • As a part of the August 2021 Patch Tuesday event, Microsoft released a total of 44 security fixes.
  • Thirteen of the patches involved a remote code execution vulnerability while another eight revolved around information disclosure. 
  • The most important patch addresses the Windows Print Spooler Remote Code Execution vulnerability.
  • Besides Print Nightmare, Microsoft also tackled the issues that came with the Petit Potam attacks.
patch tuesday 2021 august

As you are well aware by now, every second Tuesday of each month means that we are getting important updates from the Redmond company, as a part of the Patch Tuesday release.

Microsoft provided 44 security fixes for August’s Patch Tuesday, with seven of the vulnerabilities being rated critical. There were also three zero-days included in the batch and the other 37 were rated as important. 

Also important is the fact that thirteen of the patches involved a remote code execution vulnerability while another eight revolved around information disclosure. 

Three zero days errors fixes via the August 2021 Patch Tuesday

The most important patch released in the latest batch addresses the Windows Print Spooler Remote Code Execution vulnerability, which has been a major topic of discussion since it was discovered back in June.

The tech company faced major backlash from the security community for totally messing up the release of patches meant to address the issue. 

The affected tools are .NET Core & Visual Studio, ASP.NET Core & Visual Studio, Azure, Windows Update, Windows Print Spooler Components, Windows Media, Windows Defender, Remote Desktop Client, Microsoft Dynamics, Microsoft Edge (Chromium-based), Microsoft Office, Microsoft Office Word, Microsoft Office SharePoint and more.

And since we’ve mentioned that Microsoft also addressed three zero-days vulnerabilities through this update event, here is exactly what they had to deal with:

The Windows Update Medic Service Elevation of Privilege vulnerability is apparently the only one that has been exploited in the wild, according to Microsoft’s report.

One of the security experts, Allan Liska, said CVE-2021-36948 stood out to him because of its similarities to CVE-2020-17070, which was published in November 2020.

Obviously, it is bad that it is being exploited in the wild, but we saw almost the exact same vulnerability in November of 2020 but I can’t find any evidence that that was exploited in the wild. So, I wonder if this is a new focus for threat actors.

Liska later added that CVE-2021-26424 is a major vulnerability because it is a Windows TCP/IP Remote Code Execution vulnerability, that impacts Windows 7 through 10 and Windows Server 2008 through 2019.

While this vulnerability is not listed as publicly disclosed or exploited in the wild, Microsoft did label this as ‘Exploitation More Likely’ meaning that exploitation is relatively trivial. Vulnerabilities in the TCP/IP stack can be tricky. There was a lot of concern earlier this year around CVE-2021-24074, a similar vulnerability, but that has not been exploited in the wild. On the other hand, last year’s CVE-2020-16898, another similar vulnerability, has been exploited in the wild.

Microsoft fixes PrintNightmare and PetitPotam attacks

The LSA spoofing vulnerability is related to an advisory Microsoft sent out late last month about how to protect Windows domain controllers and other Windows servers from the NTLM Relay Attack known as PetitPotam.

The PetitPotam method, which was discovered in July by French researcher Gilles Lionel, takes on the NTLM Relay attack that can coerce Windows hosts to authenticate to other machines via MS-EFSRPC EfsRpcOpenFileRaw function.

Adobe also released two patches addressing 29 CVEs in Adobe Connect and Magento. This is the smallest number of patches released by Microsoft since December 2019.

This decline is mainly due to resource constraints, considering Microsoft devoted extensive time in July responding to events like PrintNightmare and PetitPotam.

Patch Tuesday August 2021 security updates

This is the complete list of resolved vulnerabilities and released advisories in the August 2021 Patch Tuesday updates.

Tag CVE ID CVE Title Severity
.NET Core & Visual Studio CVE-2021-34485 .NET Core and Visual Studio Information Disclosure Vulnerability Important
.NET Core & Visual Studio CVE-2021-26423 .NET Core and Visual Studio Denial of Service Vulnerability Important
ASP.NET Core & Visual Studio CVE-2021-34532 ASP.NET Core and Visual Studio Information Disclosure Vulnerability Important
Azure CVE-2021-36943 Azure CycleCloud Elevation of Privilege Vulnerability Important
Azure CVE-2021-33762 Azure CycleCloud Elevation of Privilege Vulnerability Important
Azure Sphere CVE-2021-26428 Azure Sphere Information Disclosure Vulnerability Important
Azure Sphere CVE-2021-26430 Azure Sphere Denial of Service Vulnerability Important
Azure Sphere CVE-2021-26429 Azure Sphere Elevation of Privilege Vulnerability Important
Microsoft Azure Active Directory Connect CVE-2021-36949 Microsoft Azure Active Directory Connect Authentication Bypass Vulnerability Important
Microsoft Dynamics CVE-2021-36946 Microsoft Dynamics Business Central Cross-site Scripting Vulnerability Important
Microsoft Dynamics CVE-2021-36950 Microsoft Dynamics 365 (on-premises) Cross-site Scripting Vulnerability Important
Microsoft Dynamics CVE-2021-34524 Microsoft Dynamics 365 (on-premises) Remote Code Execution Vulnerability Important
Microsoft Edge (Chromium-based) CVE-2021-30591 Chromium: CVE-2021-30591 Use after free in File System API Unknown
Microsoft Edge (Chromium-based) CVE-2021-30592 Chromium: CVE-2021-30592 Out of bounds write in Tab Groups Unknown
Microsoft Edge (Chromium-based) CVE-2021-30597 Chromium: CVE-2021-30597 Use after free in Browser UI Unknown
Microsoft Edge (Chromium-based) CVE-2021-30594 Chromium: CVE-2021-30594 Use after free in Page Info UI Unknown
Microsoft Edge (Chromium-based) CVE-2021-30596 Chromium: CVE-2021-30596 Incorrect security UI in Navigation Unknown
Microsoft Edge (Chromium-based) CVE-2021-30590 Chromium: CVE-2021-30590 Heap buffer overflow in Bookmarks Unknown
Microsoft Edge (Chromium-based) CVE-2021-30593 Chromium: CVE-2021-30593 Out of bounds read in Tab Strip Unknown
Microsoft Graphics Component CVE-2021-34530 Windows Graphics Component Remote Code Execution Vulnerability Critical
Microsoft Graphics Component CVE-2021-34533 Windows Graphics Component Font Parsing Remote Code Execution Vulnerability Important
Microsoft Office CVE-2021-34478 Microsoft Office Remote Code Execution Vulnerability Important
Microsoft Office SharePoint CVE-2021-36940 Microsoft SharePoint Server Spoofing Vulnerability Important
Microsoft Office Word CVE-2021-36941 Microsoft Word Remote Code Execution Vulnerability Important
Microsoft Scripting Engine CVE-2021-34480 Scripting Engine Memory Corruption Vulnerability Critical
Microsoft Windows Codecs Library CVE-2021-36937 Windows Media MPEG-4 Video Decoder Remote Code Execution Vulnerability Important
Remote Desktop Client CVE-2021-34535 Remote Desktop Client Remote Code Execution Vulnerability Critical
Windows Bluetooth Service CVE-2021-34537 Windows Bluetooth Driver Elevation of Privilege Vulnerability Important
Windows Cryptographic Services CVE-2021-36938 Windows Cryptographic Primitives Library Information Disclosure Vulnerability Important
Windows Defender CVE-2021-34471 Microsoft Windows Defender Elevation of Privilege Vulnerability Important
Windows Event Tracing CVE-2021-34486 Windows Event Tracing Elevation of Privilege Vulnerability Important
Windows Event Tracing CVE-2021-34487 Windows Event Tracing Elevation of Privilege Vulnerability Important
Windows Event Tracing CVE-2021-26425 Windows Event Tracing Elevation of Privilege Vulnerability Important
Windows Media CVE-2021-36927 Windows Digital TV Tuner device registration application Elevation of Privilege Vulnerability Important
Windows MSHTML Platform CVE-2021-34534 Windows MSHTML Platform Remote Code Execution Vulnerability Critical
Windows NTLM CVE-2021-36942 Windows LSA Spoofing Vulnerability Important
Windows Print Spooler Components CVE-2021-34483 Windows Print Spooler Elevation of Privilege Vulnerability Important
Windows Print Spooler Components CVE-2021-36947 Windows Print Spooler Remote Code Execution Vulnerability Important
Windows Print Spooler Components CVE-2021-36936 Windows Print Spooler Remote Code Execution Vulnerability Critical
Windows Services for NFS ONCRPC XDR Driver CVE-2021-36933 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
Windows Services for NFS ONCRPC XDR Driver CVE-2021-26433 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
Windows Services for NFS ONCRPC XDR Driver CVE-2021-36932 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
Windows Services for NFS ONCRPC XDR Driver CVE-2021-26432 Windows Services for NFS ONCRPC XDR Driver Remote Code Execution Vulnerability Critical
Windows Services for NFS ONCRPC XDR Driver CVE-2021-36926 Windows Services for NFS ONCRPC XDR Driver Information Disclosure Vulnerability Important
Windows Storage Spaces Controller CVE-2021-34536 Storage Spaces Controller Elevation of Privilege Vulnerability Important
Windows TCP/IP CVE-2021-26424 Windows TCP/IP Remote Code Execution Vulnerability Critical
Windows Update CVE-2021-36948 Windows Update Medic Service Elevation of Privilege Vulnerability Important
Windows Update Assistant CVE-2021-36945 Windows 10 Update Assistant Elevation of Privilege Vulnerability Important
Windows Update Assistant CVE-2021-26431 Windows Recovery Environment Agent Elevation of Privilege Vulnerability Important
Windows User Profile Service CVE-2021-34484 Windows User Profile Service Elevation of Privilege Vulnerability Important
Windows User Profile Service CVE-2021-26426 Windows User Account Profile Picture Elevation of Privilege Vulnerability Important

Recent security updates from other companies

Other companies that released updates are as follows:

What is your opinion on the recent plan of action that Microsoft turned to? Share your thoughts with us in the comments section below.