CVE-2026-81401 — Microsoft Excel Information Disclosure Vulnerability

Executive Summary

Access of resource using incompatible type ('type confusion') in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

Overview

5.5

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Weakness CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')

Released Sep 8 2026

Last Updated Sep 8 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

CVSS Vector

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

None

USER INTERACTION

Required

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 4.8

EPSS Score

No EPSS score available for this CVE.

View on FIRST.org

Affected Products

13 affected products

Product	KB Article	Severity	Impact	Restart Required
Microsoft 365 Apps for Enterprise for 32-bit Systems	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft 365 Apps for Enterprise for 64-bit Systems	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Excel 2016 (32-bit edition)	`5002914 (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Excel 2016 (64-bit edition)	`5002914 (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office 2016 (32-bit edition)	`5002904 (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office 2016 (64-bit edition)	`5002904 (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office 2019 for 32-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office 2019 for 64-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office 365 for Mac Important Information Disclosure None Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C Unknown Unknown None Microsoft Office LTSC 2021 for 32-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office LTSC 2021 for 64-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office LTSC 2024 for 32-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office LTSC 2024 for 64-bit editions	`Release Notes (Security Update)`	Important	Information Disclosure	Unknown
Microsoft Office LTSC for Mac 2021 Important Information Disclosure None Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C Unknown Unknown None Microsoft Office LTSC for Mac 2024 Important Information Disclosure None Base: 5.5 Temporal: 4.8 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C Unknown Unknown None Office Online Server	`5002910 (Security Update)`	Important	Information Disclosure	Unknown

Patches

4 patches

Article	Type	Restart
`Release Notes`	Security Update	Unknown
`5002914`	Security Update	Unknown
`5002904`	Security Update	Unknown
`5002910`	Security Update	Unknown

Exploits & PoC

No public exploit or PoC has been linked for this CVE yet. When available, references are sourced from public repositories and may be unverified or non-functional — review carefully before use.

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

Anonymous

References

MSRC Advisory MITRE NVD