CVE-2026-78439: Microsoft Office Graphics Component Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 8.8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Category
Remote Code Execution
Exploit Status
Not Exploited
Exploitation Likelihood
Less Likely
Patch Tuesday
2026-Sep
Released
2026-09-08

Description

Stack-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.

FAQ

According to the CVSS metric, the attack vector is network (AV:N) and user interaction is required (UI:R). What is the target context of the remote code execution? This attack requires a user to open a specially crafted file from the attacker to initiate remote code execution. Are the updates for the Microsoft Office LTSC for Mac currently available? The security update for Microsoft Office LTSC for Mac 2021 and 2024 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. Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector.

Affected Products (4)

Microsoft Office

  • Microsoft Office LTSC for Mac 2021
  • Microsoft Office for Android
  • Microsoft Office LTSC for Mac 2024
  • Microsoft Office 365 for Mac

Security Updates (1)

Revision History

  • 2026-09-08: Information published.