A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user.
To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Word software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or Instant Messenger message, and then convince the user to open the specially crafted file.
Note that Microsoft Outlook Preview Pane is an attack vector for this vulnerability.
The security update addresses the vulnerability by correcting how Microsoft Word handles files in memory.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Office Online Server | | [KB4484270](https://patchblox.com/security/data/fix/microsoft/kb4484270.md) | Mar 10, 2020 | | Microsoft | Microsoft SharePoint Server 2019 | | [KB4484271](https://patchblox.com/security/data/fix/microsoft/kb4484271.md) | Mar 10, 2020 | | Microsoft | Microsoft SharePoint Server 2019 | | [KB4484277](https://patchblox.com/security/data/fix/microsoft/kb4484277.md) | Mar 10, 2020 | --- Data as of 2026-11-07T18:46:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.