CVE-2021-27053: 
vulnerability analysis and mitigation

Microsoft Excel Remote Code Execution Vulnerability (CVE-2021-27053) was identified and disclosed in March 2021. The vulnerability affects various versions of Microsoft Excel and Microsoft Office products, including Excel 2010 SP2, Excel 2013 SP1, Excel 2016, Office 2019, and Microsoft 365 Apps Enterprise (NVD).

The vulnerability exists within the parsing of XLS files and results from the lack of validating the existence of an object prior to performing operations on the object. It has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with the vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. The flaw is specifically characterized as a use-after-free vulnerability that could lead to remote code execution (ZDI).

If successfully exploited, this vulnerability allows attackers to execute arbitrary code in the context of the current process on affected installations of Microsoft Excel. The potential impact includes complete compromise of system confidentiality, integrity, and availability (ZDI).

The vulnerability requires user interaction for exploitation, specifically the target must visit a malicious page or open a malicious file. This interaction requirement somewhat mitigates the ease of exploitation (ZDI).

Microsoft has released security updates to address this vulnerability. Users are advised to apply the appropriate patches through Microsoft's official update channels (NVD).