CVE-2026-20955

Published: Jan 13, 2026Modified: Jan 14, 2026

7.8

Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitability: 1.8 / Impact: 5.9

Source: secure@microsoft.com

Description

Untrusted pointer dereference in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Affected (11)

Products: Microsoft: 365 Apps, Office, Office Long Term Servicing Channel, Office Online Server

4 products

Office Long Term Servicing Channel

Office Online Server

Configuration A

11 vulnerable

Vulnerable Software	Affected Versions
Microsoft 365 Apps	All versions
Microsoft 365 Apps	All versions
Microsoft Office	Version 2019
Microsoft Office	Version 2019
Microsoft Office Long Term Servicing Channel	Version 2021
Microsoft Office Long Term Servicing Channel	Version 2021
Microsoft Office Long Term Servicing Channel	Version 2021
Microsoft Office Long Term Servicing Channel	Version 2024
Microsoft Office Long Term Servicing Channel	Version 2024
Microsoft Office Long Term Servicing Channel	Version 2024
Microsoft Office Online Server	Before 16.0.10417.20083

Related CWEs

Untrusted Pointer Dereference

The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20955

Source: secure@microsoft.com

Vendor Advisory

Timeline

No history available yet.