CVE-2026-55142: Microsoft Word Information Disclosure Vulnerability

Overview

Severity

Medium (CVSS 5.5)

CVSS 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

Category

Information Disclosure

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Jul

Released

2026-07-14

Description

Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to disclose information locally.

FAQ

What type of information could be disclosed by this vulnerability? An attacker who successfully exploited this vulnerability could potentially read portions of heap memory. Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. 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 (14)

Microsoft Office

• Microsoft Office 365 for Mac
• Microsoft SharePoint Enterprise Server 2016
• Microsoft SharePoint Server 2019
• Microsoft Office 2019 for 32-bit editions
• Microsoft Office 2019 for 64-bit editions
• Microsoft 365 Apps for Enterprise for 32-bit Systems
• Microsoft 365 Apps for Enterprise for 64-bit Systems
• Microsoft Office LTSC 2021 for 64-bit editions
• Microsoft Office LTSC 2021 for 32-bit editions
• Microsoft SharePoint Server Subscription Edition
• Microsoft Office LTSC 2024 for 32-bit editions
• Microsoft Office LTSC 2024 for 64-bit editions
• Microsoft Word 2016 (32-bit edition)
• Microsoft Word 2016 (64-bit edition)

Security Updates (7)

• Release Notes
• 5002891
• 5002892
• 5002883
• 5002885
• 5002882
• 5002890

Acknowledgments

Haein Lee with KAIST Hacking Lab

Revision History

• 2026-07-14: Information published.