CVE-2026-50678: Microsoft Excel Information Disclosure Vulnerability

Overview

Severity
Medium (CVSS 6.6)
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Jul
Released
2026-07-14

Description

Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

FAQ

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

Affected Products (14)

Microsoft Office

  • Office Online Server
  • 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 for Mac 2021
  • Microsoft Office LTSC 2021 for 64-bit editions
  • Microsoft Office LTSC 2021 for 32-bit editions
  • Microsoft Office LTSC 2024 for 32-bit editions
  • Microsoft Office LTSC 2024 for 64-bit editions
  • Microsoft Office LTSC for Mac 2024
  • Microsoft Excel 2016 (32-bit edition)
  • Microsoft Excel 2016 (64-bit edition)
  • Microsoft Office 365 for Mac

Security Updates (4)

Acknowledgments

<a href="https://x.com/dnpushme">f4 &amp; Zhiniang Peng with HUST</a>

Revision History

  • 2026-07-14: Information published.