Main Vulnerability Database Vulnerabilities #VU121282

Untrusted Pointer Dereference in Microsoft products - CVE-2026-20955

Published: January 13, 2026

Vulnerability identifier: #VU121282

CSH Severity: High

CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-20955

CWE-ID: CWE-822

Exploitation vector: Remote access

Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to untrusted pointer dereference in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted file and execute arbitrary code on the system.

Affected software

Office Online Server
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Office LTSC

How to mitigate CVE-2026-20955

Install updates from vendor's website.

External References

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

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