Today is Microsoft's December 2021 Patch Tuesday, and with it comes fixes for six zero-day vulnerabilities and a total of 67 flaws. These updates include a fix for an actively exploited Windows Installer vulnerability used in malware distribution campaigns.

Microsoft has fixed 55 vulnerabilities (not including Microsoft Edge) with today's update, with seven classified as Critical and 60 as Important.

The number of each type of vulnerability is listed below:

21 Elevation of Privilege Vulnerabilities 26 Remote Code Execution Vulnerabilities 10 Information Disclosure Vulnerabilities 3 Denial of Service Vulnerabilities 7 Spoofing Vulnerabilities

For information about the non-security Windows updates, you can read about today's Windows 10 KB5008212 & KB5008206 updates released.

Six zero-days fixed, with two actively exploited

December's Patch Tuesday includes fixes for six zero-day vulnerabilities, with one actively exploited Windows AppX Installer vulnerability.

Microsoft classifies a vulnerability as a zero-day if it is publicly disclosed or actively exploited with no official fix available.

The actively exploited Windows AppX Installer zero-day vulnerability is tracked as CVE-2021-43890 and is used in various malware distribution campaigns, including Emotet, TrickBot, and BazarLoader.

Windows AppX Installer abused to install EmotetWindows AppX Installer abused to install Emotet
Source: BleepingComputer

Microsoft also fixed five publicly disclosed zero-day vulnerabilities as part of the December 2021 Patch Tuesday that are not known to be exploited in attacks.

CVE-2021-43240 - NTFS Set Short Name Elevation of Privilege Vulnerability CVE-2021-41333 - Windows Print Spooler Elevation of Privilege Vulnerability CVE-2021-43880 - Windows Mobile Device Management Elevation of Privilege Vulnerability CVE-2021-43883 - Windows Installer Elevation of Privilege Vulnerability CVE-2021-43893 - Windows Encrypting File System (EFS) Elevation of Privilege Vulnerability

Recent updates from other companies

Other vendors who released updates in November include:

Android's December security updates were released last week. Apache Log4j: Numerous security advisories were released for the highly problematic vulnerability sweeping the Internet. Apple released security updates for iOS, iPadOS, macOS, tvOS and watchOS. Cisco released security updates for numerous products this month, including advisories related to the Log4j vulnerability in their products. SAP released its December 2021 security updates. VMWare released an advisory about current patches for the Log4j vulnerability in their products.

The December 2021 Patch Tuesday Security Updates

Below is the complete list of resolved vulnerabilities and released advisories in the December 2021 Patch Tuesday updates. To access the full description of each vulnerability and the systems that it affects, you can view the full report here.

 

TagCVE IDCVE TitleSeverity
Apps CVE-2021-43890 Windows AppX Installer Spoofing Vulnerability Important
ASP.NET Core & Visual Studio CVE-2021-43877 ASP.NET Core and Visual Studio Elevation of Privilege Vulnerability Important
Azure Bot Framework SDK CVE-2021-43225 Bot Framework SDK Remote Code Execution Vulnerability Important
BizTalk ESB Toolkit CVE-2021-43892 Microsoft BizTalk ESB Toolkit Spoofing Vulnerability Important
Internet Storage Name Service CVE-2021-43215 iSNS Server Memory Corruption Vulnerability Can Lead to Remote Code Execution Critical
Microsoft Defender for IoT CVE-2021-41365 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-42311 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-42310 Microsoft Defender for IoT Remote Code Execution Vulnerability Critical
Microsoft Defender for IoT CVE-2021-43882 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-43888 Microsoft Defender for IoT Information Disclosure Vulnerability Important
Microsoft Defender for IoT CVE-2021-42314 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-42313 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-42312 Microsoft Defender for IOT Elevation of Privilege Vulnerability Important
Microsoft Defender for IoT CVE-2021-43889 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Defender for IoT CVE-2021-42315 Microsoft Defender for IoT Remote Code Execution Vulnerability Important
Microsoft Devices CVE-2021-43899 Microsoft 4K Wireless Display Adapter Remote Code Execution Vulnerability Critical
Microsoft Edge (Chromium-based) CVE-2021-4056 Chromium: CVE-2021-4056: Type Confusion in loader Unknown
Microsoft Edge (Chromium-based) CVE-2021-4055 Chromium: CVE-2021-4055 Heap buffer overflow in extensions Unknown
Microsoft Edge (Chromium-based) CVE-2021-4054 Chromium: CVE-2021-4054 Incorrect security UI in autofill Unknown
Microsoft Edge (Chromium-based) CVE-2021-4052 Chromium: CVE-2021-4052 Use after free in web apps Unknown
Microsoft Edge (Chromium-based) CVE-2021-4053 Chromium: CVE-2021-4053 Use after free in UI Unknown
Microsoft Edge (Chromium-based) CVE-2021-4065 Chromium: CVE-2021-4065 Use after free in autofill Unknown
Microsoft Edge (Chromium-based) CVE-2021-4064 Chromium: CVE-2021-4064 Use after free in screen capture Unknown
Microsoft Edge (Chromium-based) CVE-2021-4063 Chromium: CVE-2021-4063 Use after free in developer tools Unknown
Microsoft Edge (Chromium-based) CVE-2021-4068 Chromium: CVE-2021-4068 Insufficient validation of untrusted input in new tab page Unknown
Microsoft Edge (Chromium-based) CVE-2021-4067 Chromium: CVE-2021-4067 Use after free in window manager Unknown
Microsoft Edge (Chromium-based) CVE-2021-4066 Chromium: CVE-2021-4066 Integer underflow in ANGLE Unknown
Microsoft Edge (Chromium-based) CVE-2021-4059 Chromium: CVE-2021-4059 Insufficient data validation in loader Unknown
Microsoft Edge (Chromium-based) CVE-2021-4062 Chromium: CVE-2021-4062 Heap buffer overflow in BFCache Unknown
Microsoft Edge (Chromium-based) CVE-2021-4061 Chromium: CVE-2021-4061 Type Confusion in V8 Unknown
Microsoft Edge (Chromium-based) CVE-2021-4058 Chromium: CVE-2021-4058 Heap buffer overflow in ANGLE Unknown
Microsoft Edge (Chromium-based) CVE-2021-4057 Chromium: CVE-2021-4057 Use after free in file API Unknown
Microsoft Local Security Authority Server (lsasrv) CVE-2021-43216 Microsoft Local Security Authority Server (lsasrv) Information Disclosure Vulnerability Important
Microsoft Message Queuing CVE-2021-43236 Microsoft Message Queuing Information Disclosure Vulnerability Important
Microsoft Message Queuing CVE-2021-43222 Microsoft Message Queuing Information Disclosure Vulnerability Important
Microsoft Office CVE-2021-43875 Microsoft Office Graphics Remote Code Execution Vulnerability Important
Microsoft Office CVE-2021-42295 Visual Basic for Applications Information Disclosure Vulnerability Important
Microsoft Office CVE-2021-43905 Microsoft Office app Remote Code Execution Vulnerability Critical
Microsoft Office Access CVE-2021-42293 Microsoft Jet Red Database Engine and Access Connectivity Engine Elevation of Privilege Vulnerability Important
Microsoft Office Excel CVE-2021-43256 Microsoft Excel Remote Code Execution Vulnerability Important
Microsoft Office SharePoint CVE-2021-42309 Microsoft SharePoint Server Remote Code Execution Vulnerability Important
Microsoft Office SharePoint CVE-2021-42320 Microsoft SharePoint Server Spoofing Vulnerability Important
Microsoft Office SharePoint CVE-2021-43242 Microsoft SharePoint Server Spoofing Vulnerability Important
Microsoft Office SharePoint CVE-2021-42294 Microsoft SharePoint Server Remote Code Execution Vulnerability Important
Microsoft PowerShell CVE-2021-43896 Microsoft PowerShell Spoofing Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-41360 HEVC Video Extensions Remote Code Execution Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-43248 Windows Digital Media Receiver Elevation of Privilege Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-43214 Web Media Extensions Remote Code Execution Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-40452 HEVC Video Extensions Remote Code Execution Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-40453 HEVC Video Extensions Remote Code Execution Vulnerability Important
Microsoft Windows Codecs Library CVE-2021-43243 VP9 Video Extensions Information Disclosure Vulnerability Important
Office Developer Platform CVE-2021-43255 Microsoft Office Trust Center Spoofing Vulnerability Important
Remote Desktop Client CVE-2021-43233 Remote Desktop Client Remote Code Execution Vulnerability Critical
Role: Windows Fax Service CVE-2021-43234 Windows Fax Service Remote Code Execution Vulnerability Important
Role: Windows Hyper-V CVE-2021-43246 Windows Hyper-V Denial of Service Vulnerability Important
Visual Studio Code CVE-2021-43891 Visual Studio Code Remote Code Execution Vulnerability Important
Visual Studio Code CVE-2021-43908 Visual Studio Code Spoofing Vulnerability Important
Visual Studio Code - WSL Extension CVE-2021-43907 Visual Studio Code WSL Extension Remote Code Execution Vulnerability Critical
Windows Common Log File System Driver CVE-2021-43226 Windows Common Log File System Driver Elevation of Privilege Vulnerability Important
Windows Common Log File System Driver CVE-2021-43224 Windows Common Log File System Driver Information Disclosure Vulnerability Important
Windows Common Log File System Driver CVE-2021-43207 Windows Common Log File System Driver Elevation of Privilege Vulnerability Important
Windows Digital TV Tuner CVE-2021-43245 Windows Digital TV Tuner Elevation of Privilege Vulnerability Important
Windows DirectX CVE-2021-43219 DirectX Graphics Kernel File Denial of Service Vulnerability Important
Windows Encrypting File System (EFS) CVE-2021-43217 Windows Encrypting File System (EFS) Remote Code Execution Vulnerability Critical
Windows Encrypting File System (EFS) CVE-2021-43893 Windows Encrypting File System (EFS) Elevation of Privilege Vulnerability Important
Windows Event Tracing CVE-2021-43232 Windows Event Tracing Remote Code Execution Vulnerability Important
Windows Installer CVE-2021-43883 Windows Installer Elevation of Privilege Vulnerability Important
Windows Kernel CVE-2021-43244 Windows Kernel Information Disclosure Vulnerability Important
Windows Media CVE-2021-40441 Windows Media Center Elevation of Privilege Vulnerability Important
Windows Mobile Device Management CVE-2021-43880 Windows Mobile Device Management Elevation of Privilege Vulnerability Important
Windows NTFS CVE-2021-43240 NTFS Set Short Name Elevation of Privilege Vulnerability Important
Windows NTFS CVE-2021-43231 Windows NTFS Elevation of Privilege Vulnerability Important
Windows NTFS CVE-2021-43230 Windows NTFS Elevation of Privilege Vulnerability Important
Windows NTFS CVE-2021-43229 Windows NTFS Elevation of Privilege Vulnerability Important
Windows Print Spooler Components CVE-2021-41333 Windows Print Spooler Elevation of Privilege Vulnerability Important
Windows Remote Access Connection Manager CVE-2021-43223 Windows Remote Access Connection Manager Elevation of Privilege Vulnerability Important
Windows Remote Access Connection Manager CVE-2021-43238 Windows Remote Access Elevation of Privilege Vulnerability Important
Windows Storage CVE-2021-43235 Storage Spaces Controller Information Disclosure Vulnerability Important
Windows Storage Spaces Controller CVE-2021-43227 Storage Spaces Controller Information Disclosure Vulnerability Important
Windows SymCrypt CVE-2021-43228 SymCrypt Denial of Service Vulnerability Important
Windows TCP/IP CVE-2021-43247 Windows TCP/IP Driver Elevation of Privilege Vulnerability Important
Windows Update Stack CVE-2021-43237 Windows Setup Elevation of Privilege Vulnerability Important
Windows Update Stack CVE-2021-43239 Windows Recovery Environment Agent Elevation of Privilege Vulnerability Important