CVE-2026-66807

HIGHCVSS 7.8/10

Last modified

CVE-2026-66807 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. Stack-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally..

Description

Stack-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
MicrosoftMicrosoft 365 Apps for Enterprise>= 16.0.1, < https://aka.ms/OfficeSecurityReleases
MicrosoftMicrosoft Office 2019>= 19.0.0, < https://aka.ms/OfficeSecurityReleases
MicrosoftMicrosoft Office 365 for Mac>= 1.0.0, < 16.112.26081010
MicrosoftMicrosoft Office LTSC 2021>= 16.0.1, < https://aka.ms/OfficeSecurityReleases
MicrosoftMicrosoft Office LTSC 2024>= 16.0.0, < https://aka.ms/OfficeSecurityReleases
MicrosoftMicrosoft Office LTSC for Mac 2021>= 16.0.1, < 16.112.26081010
MicrosoftMicrosoft Office LTSC for Mac 2024>= 16.0.0, < 16.112.26081010

References

Timeline

Published
Last Modified
Status
Undergoing Analysis

Frequently Asked Questions

What is CVE-2026-66807?
Stack-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
How severe is CVE-2026-66807?
CVE-2026-66807 has a CVSS score of 7.8/10 (HIGH severity).
How do I fix CVE-2026-66807?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST