MSRC-CVE-2026-81393 — Microsoft Excel Information Disclosure Vulnerability

Summary

Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

Is the Preview Pane an attack vector for this vulnerability?
No, the Preview Pane is not an attack vector.

What type of information could be disclosed by this vulnerability?
The type of information that could be disclosed if an attacker successfully exploited this vulnerability is uninitialized heap memory.

Are the updates for Microsoft Office LTSC for Mac 2021 and 2024 currently available?
Yes. As of September 16, 2026, the security update for Microsoft Office LTSC for Mac 2021, 2024 and Microsoft Office 365 for Mac are available. Customers running Microsoft Office LTSC for Mac 2021, 2024 and Microsoft Office 365 for Mac should ensure the update is installed to be protected from this vulnerability.

Security updates
16.0.10417.20207 — https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
16.0.20326.20138 — https://docs.microsoft.com/en-us/officeupdates/office365-proplus-security-updates
16.113.26091433 — https://go.microsoft.com/fwlink/p/?linkid=831049
16.0.5569.1003 — https://support.microsoft.com/help/5002914
16.0.5569.1003 — https://support.microsoft.com/help/5002904
16.113.26091433 — https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c

Vulnerabilities 1

Medium 5.5

CVE-2026-81393

Microsoft Excel Information Disclosure Vulnerability

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Microsoft Microsoft 365 Apps for Enterprise Microsoft Office LTSC 2021 Microsoft Office LTSC 2024

Sep 8, 2026

Revision history

2026-09-17 #2
Microsoft is announcing the availability of the security updates for Microsoft Office for Mac. Customers running affected Mac software should install the update for their product to be protected from this vulnerability. Customers running other Microsoft Office software do not need to take any action. See the [Release Notes](https://go.microsoft.com/fwlink/p/?linkid=831049) for more information and download links.
2026-09-08 #1
Information published.

References

CVE-2026-81393 Microsoft Excel Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81393
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss