CVE-2026-55121: Microsoft Office Information Disclosure Vulnerability
Published Jul 14, 2026
·Updated
Microsoft Office Information Disclosure Vulnerability
Other sources
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
— Microsoft
Affected Software
32 affected componentsFixes available
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft SharePoint Enterprise Server 2016<16.0.5561.1001
16.0.5561.1001
Microsoft Office 365 for Mac<16.111.26071215
16.111.26071215
Microsoft Office 2019 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2016<16.0.5561.1000
16.0.5561.1000
Microsoft Office LTSC for Mac 2021<16.111.26071215
16.111.26071215
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft SharePoint Server 2019<16.0.10417.20175
16.0.10417.20175
Microsoft Office LTSC 2024 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2016<16.0.5561.1000
16.0.5561.1000
Microsoft SharePoint Server Subscription Edition<16.0.19725.20434
16.0.19725.20434
Microsoft Office LTSC 2021 for 32-bit editions<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 for Mac 2024<16.111.26071215
16.111.26071215
Microsoft Office LTSC 2024 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps
Microsoft 365 Apps
Microsoft Microsoft 365 Macos
Microsoft Office 2016
Microsoft Office 2016
Microsoft Office 2019
Microsoft Office 2019
Microsoft Office 2021
Microsoft Office 2021
Microsoft Office 2021 Macos
Microsoft Office 2024
Microsoft Office 2024
Microsoft Office 2024 Macos
Microsoft SharePoint Server<16.0.19725.20434
Microsoft SharePoint Server=2016
Microsoft SharePoint Server=2019
Remediation
Event History
Jul 14, 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·05:10 PM
Data Sourced
via MITRE·05:10 PM
DescriptionSeverity
Data Sourced
via NVD·06:18 PM
RemedyDescriptionSeverityWeaknessAffected Software
Frequently Asked Questions
1
What is the severity of CVE-2026-55121?
The severity of CVE-2026-55121 is rated as medium with a CVSS score of 5.5.
2
How do I fix CVE-2026-55121?
To fix CVE-2026-55121, apply the available patches from Microsoft for affected Microsoft Office products.
3
What products are affected by CVE-2026-55121?
CVE-2026-55121 affects Microsoft Office 2016, Office 2019, Office 2021, Office 2024, Microsoft 365 Apps, and SharePoint Server.
4
What types of attacks are possible with CVE-2026-55121?
CVE-2026-55121 allows unauthorized attackers to disclose information locally through an out-of-bounds read.
5
When was CVE-2026-55121 published?
CVE-2026-55121 was published on July 14, 2026.