CVE-2026-63521: Microsoft Office Word Information Disclosure Vulnerability
Published Aug 11, 2026
·Updated
Microsoft Office Word Information Disclosure Vulnerability
Other sources
Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
— Microsoft
Affected Software
20 affected componentsFixes available
Microsoft Office LTSC 2024 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Word 2016<16.0.5565.1000
16.0.5565.1000
Microsoft Office LTSC 2021 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Word 2016<16.0.5565.1000
16.0.5565.1000
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps
Microsoft 365 Apps
Microsoft Office 2019
Microsoft Office 2019
Microsoft Office 2021
Microsoft Office 2021
Microsoft Office 2024
Microsoft Office 2024
Microsoft Word=2016
Microsoft Word=2016
Remediation
Event History
Aug 11, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·05:04 PM
Data Sourced
via MITRE·05:04 PM
DescriptionSeverity
Data Sourced
via NVD·05:18 PM
RemedyDescriptionSeverityWeaknessAffected Software
Frequently Asked Questions
1
What is the severity of CVE-2026-63521?
The severity of CVE-2026-63521 is medium with a score of 5.5.
2
How do I fix CVE-2026-63521?
To fix CVE-2026-63521, ensure that you update Microsoft Office Word to the latest version provided by Microsoft.
3
What type of vulnerability is CVE-2026-63521?
CVE-2026-63521 is an information disclosure vulnerability due to an out-of-bounds read.
4
Who is affected by CVE-2026-63521?
CVE-2026-63521 affects Microsoft Office Word 2016, Microsoft 365 Apps for Enterprise, and various versions of Microsoft Office LTSC and Office 2019.
5
What does CVE-2026-63521 allow an attacker to do?
CVE-2026-63521 allows an unauthorized attacker to disclose information locally.