CVE-2025-29979: Microsoft Excel Remote Code Execution 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

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2025-May

Released

2025-05-13

Last Updated

2025-05-14

EPSS Score

0.74% (percentile: 73.0%)

Description

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

FAQ

Is the Preview Pane an attack vector for this vulnerability? No, the Preview Pane is not an attack vector. According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution? The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally. For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer. Are the updates for Microsoft Office LTSC for Mac 2021 and 2024 currently available? Yes. As of May 14, 2025, the security update for Microsoft Office LTSC for Mac 2021 and 2024 are available. Customers running Microsoft Office LTSC for Mac 2021 and 2024 should ensure the update is installed to be protected from this vulnerability.

Affected Products (13)

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 Office 2016 (32-bit edition)
• Microsoft Office 2016 (64-bit edition)

Security Updates (1)

• Release Notes

Acknowledgments

f4 & Zhiniang Peng with HUST

Revision History

• 2025-05-13: Information published.
• 2025-05-14: Microsoft is announcing the availability of the security updates for Microsoft Office for Mac. Customers running affected Mac software should install the update for their product to be protected from this vulnerability. Customers running other Microsoft Office software do not need to take any action. See the Release Notes for more information and download links.