Reliance on Untrusted Inputs in a Security Decision in Microsoft products - CVE-2026-21514
Published: February 10, 2026
Vulnerability identifier: #VU122540
CSH Severity: Critical
CVSS v4.0: 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/E:A/U:Red
CVE-ID: CVE-2026-21514
CWE-ID: CWE-807
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: Microsoft
Affected software:
Microsoft Office
Microsoft Office for macOS
Microsoft 365 Apps for Enterprise
Microsoft Office
Microsoft Office for macOS
Microsoft 365 Apps for Enterprise
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to insufficient mitigations for COM/OLE controls. A remote attacker can trick the victim into opening a specially crafted Word file, bypass implemented OLE mitigations and execute arbitrary code on the system.
Note, the vulnerability is being actively exploited in the wild.
How to mitigate CVE-2026-21514
Install updates from vendor's website.