Security News > 2021 > November > Microsoft patches actively exploited Exchange, Excel zero-days (CVE-2021-42321, CVE-2021-42292)

It's a light November 2021 Patch Tuesday from Microsoft: 55 fixed CVEs, of which two are zero-days under active exploitation: CVE-2021-42321, a Microsoft Exchange RCE, and CVE-2021-42292, a Microsoft Excel security feature bypass bug.
CVE-2021-42321, the remote code execution vulnerability in Microsoft Exchange Server 2016 and 2019, is due to issues with the validation of command-let arguments.
In a blog post published by the Exchange Team, the company recommended that the provided updates for Microsoft Exchange be installed immediately.
The in-the-wild exploitation of CVE-2021-42292, the Microsoft Excel security feature bypass zero-day, was apparently discovered by Microsoft's Security Threat Intelligence Center.
CVE-2021-42298, a Microsoft Defender RCE hole that will be plugged automatically on internet-connected systems when they receive the malware definition updates and the update for the Microsoft Malware Protection Engine.
CVE-2021-26443 a RCE affecting Microsoft Virtual Machine Bus that may allow a guest-to-host escape.
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Related Vulnerability
DATE | CVE | VULNERABILITY TITLE | RISK |
---|---|---|---|
2021-11-10 | CVE-2021-42321 | Unspecified vulnerability in Microsoft Exchange Server 2016/2019 Microsoft Exchange Server Remote Code Execution Vulnerability | 0.0 |
2021-11-10 | CVE-2021-42298 | Code Injection vulnerability in Microsoft Malware Protection Engine Microsoft Defender Remote Code Execution Vulnerability | 0.0 |
2021-11-10 | CVE-2021-42292 | Unspecified vulnerability in Microsoft products Microsoft Excel Security Feature Bypass Vulnerability | 0.0 |
2021-11-10 | CVE-2021-26443 | Unspecified vulnerability in Microsoft products Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability | 0.0 |