Type Confusion in Microsoft products - CVE-2026-81401
Published: September 9, 2026
Vulnerability identifier: #VU148294
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-81401
CWE-ID: CWE-843
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose information.
The vulnerability exists due to access of a resource using an incompatible type in Microsoft Office Excel when processing input. A remote attacker can exploit the type confusion vulnerability to disclose information.
The Preview Pane is not an attack vector.
Affected software
Microsoft Excel
Microsoft 365 Apps for Enterprise
Microsoft Office
Office Online Server
Microsoft 365 Apps for Enterprise
Microsoft Office
Office Online Server
How to mitigate CVE-2026-81401
Install security update from vendor's website.
Microsoft Excel - update to 16.0.5569.1003
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.5569.1003, 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976
Office Online Server - update to 16.0.10417.20207
Microsoft 365 Apps for Enterprise - update to 16.0.20326.20138
Microsoft Office - addressed in versions 16.0.5569.1003, 16.0.10417.20207, 16.0.14334.20906, 16.0.17932.20976
Office Online Server - update to 16.0.10417.20207