CVE-2026-44822: Microsoft Excel Information Disclosure Vulnerability

Overview

Severity
High (CVSS 8.2)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N/E:U/RL:O/RC:C
Category
Information Disclosure
Exploit Status
Not Exploited
Exploitation Likelihood
Unlikely
Patch Tuesday
2026-Jun
Released
2026-06-09

Description

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

FAQ

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. Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. Are the updates for the Microsoft Office LTSC and Microsoft 365 for Mac currently available? The security update for Microsoft Office LTSC for Mac 2021, 2024 and Microsoft 365 for Mac are not immediately available. The updates will be released as soon as possible, and when they are available, customers will be notified via a revision to this CVE information. According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), and some loss of integrity (I:L), but no loss of availability (A:N). What does that mean for this vulnerability? An attacker who successfully exploited this vulnerability could view sensitive information, (Confidentiality), and make some changes to disclosed information (Integrity), but they would not be able to affect Availability.

Affected Products (14)

Microsoft Office

  • Microsoft Office 365 for Mac
  • 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)

Security Updates (2)

Acknowledgments

41ae55e9310ff27fa6f26af4727e5590

Revision History

  • 2026-06-09: Information published.