CVE-2026-81957: Microsoft Excel Remote Code Execution Vulnerability
Overview
- Severity
- High (CVSS 7.8)
- 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
- Category
- Remote Code Execution
- Exploit Status
- Not Exploited
- Exploitation Likelihood
- Less Likely
- Patch Tuesday
- 2026-Sep
- Released
- 2026-09-08
Description
Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
FAQ
Are the updates for the Microsoft Office LTSC for Mac currently available?
The security update for Microsoft Office LTSC for Mac 2021 and 2024 are not immediately available. The updates will be released as soon as possible, and when they are available, customers will be notified via a revision to this CVE information.
Is the Preview Pane an attack vector for this vulnerability?
No, the Preview Pane is not an attack vector.
According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
An attacker must send a user a malicious Office file and convince them to open it.
Affected Products (15)
Microsoft Office
- Microsoft Office 2019 for 32-bit editions
- Microsoft Office 2019 for 64-bit editions
- Microsoft 365 Apps for Enterprise for 32-bit Systems
- Microsoft 365 Apps for Enterprise for 64-bit Systems
- Microsoft Office LTSC for Mac 2021
- Microsoft Office LTSC 2021 for 64-bit editions
- Microsoft Office LTSC 2021 for 32-bit editions
- Microsoft Office LTSC 2024 for 32-bit editions
- Microsoft Office LTSC 2024 for 64-bit editions
- Microsoft Office LTSC for Mac 2024
- Microsoft Excel 2016 (32-bit edition)
- Microsoft Excel 2016 (64-bit edition)
- Microsoft Office 2016 (32-bit edition)
- Microsoft Office 2016 (64-bit edition)
- Microsoft Office 365 for Mac
Security Updates (2)
Acknowledgments
<a href="https://www.linkedin.com/in/haaeein">Haein Lee</a> with KAIST Hacking Lab
Revision History
- 2026-09-08: Information published.