CVE-2026-108433: Microsoft Office Word Security Feature Bypass 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

Security Feature Bypass

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Oct

Released

2026-10-15

Last Updated

2026-10-15

Description

Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.

FAQ

Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. What kind of security feature could be bypassed by successfully exploiting this vulnerability? This update addresses a vulnerability that bypasses OLE mitigations in Microsoft 365 and Microsoft Office which protect users from vulnerable COM/OLE controls. 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 (9)

Microsoft Office

• Microsoft Office LTSC for Mac 2021
• Microsoft Office LTSC for Mac 2024
• Microsoft Office 365 for Mac
• Microsoft Office LTSC 2021 for 64-bit editions
• Microsoft Office LTSC 2021 for 32-bit editions
• Microsoft Office LTSC 2024 for 64-bit editions
• Microsoft Office LTSC 2024 for 32-bit editions
• Microsoft 365 Apps for Enterprise for 64-bit Systems
• Microsoft 365 Apps for Enterprise for 32-bit Systems

Security Updates (3)

• Release Notes
• Release Notes
• Release Notes

Acknowledgments

OSORI

Revision History

• 2026-10-15: Information published.
• 2026-10-15: Information published. This CVE was addressed by updates that were released in October 2026, but the CVE was inadvertently omitted from the October 2026 Security Updates. This is an informational change only. Customers who have already installed the October 2026 updates do not need to take any further action.