CVE-2021-28453 — Microsoft Word Remote Code Execution Vulnerability

Executive Summary

None

Overview

7.8

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Remote Code Execution

Released Apr 13 2021

Last Updated Apr 13 2021

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.04068 — 0.89361 percentile

NVD CVSS 7.8 HIGH — matches MSRC

CVSS 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

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.8

EPSS Score

0.04068

probability of exploitation in the next 30 days

0.89361 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

19 affected products

Product	KB Article	Severity	Impact	Restart Required
Microsoft 365 Apps for Enterprise for 32-bit Systems	`Click to Run (Security Update)`	Important	Remote Code Execution	No
Microsoft 365 Apps for Enterprise for 64-bit Systems	`Click to Run (Security Update)`	Important	Remote Code Execution	No
Microsoft Office 2010 Service Pack 2 (32-bit editions)	`4493215 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Office 2010 Service Pack 2 (64-bit editions)	`4493215 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Office 2019 for 32-bit editions	`Click to Run (Security Update)`	Important	Remote Code Execution	No
Microsoft Office 2019 for 64-bit editions	`Click to Run (Security Update)`	Important	Remote Code Execution	No
Microsoft Office 2019 for Mac	`Release Notes (Security Update)`	Important	Remote Code Execution	No
Microsoft Office Online Server	`4504714 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Office Web Apps 2010 Service Pack 2	`4504705 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Office Web Apps Server 2013 Service Pack 1	`4504729 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft SharePoint Enterprise Server 2013 Service Pack 1	`4493201 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft SharePoint Enterprise Server 2016 4504719 (Security Update) 4504723 (Security Update) Important Remote Code Execution 4493232 4493199 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Maybe None Microsoft SharePoint Server 2010 Service Pack 2	`4504701 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft SharePoint Server 2019 4504716 (Security Update) 4504715 (Security Update) Important Remote Code Execution 4493230 4493231 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Maybe 4504716 4504715 Microsoft Word 2010 Service Pack 2 (32-bit editions)	`4493218 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2010 Service Pack 2 (64-bit editions)	`4493218 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2013 RT Service Pack 1	`4493208 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2013 Service Pack 1 (32-bit editions)	`4493208 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2013 Service Pack 1 (64-bit editions)	`4493208 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2016 (32-bit edition)	`4493198 (Security Update)`	Important	Remote Code Execution	Maybe
Microsoft Word 2016 (64-bit edition)	`4493198 (Security Update)`	Important	Remote Code Execution	Maybe

Patches

11 patches

Article	Type	Restart
`Click to Run`	Security Update	No
`4493215`	Security Update	Maybe
`Release Notes`	Security Update	No
`4504714`	Security Update	Maybe
`4504705`	Security Update	Maybe
`4504729`	Security Update	Maybe
`4493201`	Security Update	Maybe
`4504701`	Security Update	Maybe
`4493218`	Security Update	Maybe
`4493208`	Security Update	Maybe
`4493198`	Security Update	Maybe

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

kdot working with Trend Micro Zero Day Initiative

References

MSRC Advisory MITRE NVD