CVE-2026-55140: Microsoft Office Remote Code Execution Vulnerability
Published Jul 14, 2026
·Updated
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
Other sources
Microsoft Office Remote Code Execution Vulnerability
— Microsoft
Affected Software
27 affected componentsFixes available
Microsoft Office
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC for Mac 2021<16.111.26071215
16.111.26071215
Microsoft Office 2016<16.0.5561.1000, <16.0.5561.1001
16.0.5561.100016.0.5561.1001
Microsoft Office 365 for Mac<16.111.26071215
16.111.26071215
Microsoft Office 2019 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2016<16.0.5561.1000, <16.0.5561.1001
16.0.5561.100016.0.5561.1001
Microsoft Office LTSC 2024 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 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 32-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 2021 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
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·05:09 PM
Data Sourced
via MITRE·05:09 PM
DescriptionSeverity
Data Sourced
via NVD·06:18 PM
RemedyDescriptionSeverityWeaknessAffected Software
Frequently Asked Questions
1
What is the severity of CVE-2026-55140?
CVE-2026-55140 has a severity score of 7.8, classified as high.
2
How do I fix CVE-2026-55140?
The recommended fix for CVE-2026-55140 is to apply the latest security patch provided by Microsoft.
3
What software is affected by CVE-2026-55140?
CVE-2026-55140 affects Microsoft Office 2016, Microsoft 365 Apps, Microsoft Office 2019, Microsoft Office 2021, Microsoft Office 2024, and Microsoft Office LTSC for Mac 2021.
4
What type of vulnerability is CVE-2026-55140?
CVE-2026-55140 is a heap-based buffer overflow vulnerability.
5
What is the impact of CVE-2026-55140?
CVE-2026-55140 allows an unauthorized attacker to execute code locally on the affected Microsoft Office applications.