What’s Vulnerable › Vulnerabilities

CVE-2020-16955: Microsoft Office Click-to-Run Elevation of Privilege Vulnerability

• Severity: medium (CVSS 6.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-10-16 · updated 2026-06-17

Description

<p>An elevation of privilege vulnerability exists in the way that Microsoft Office Click-to-Run (C2R) AppVLP handles certain files. An attacker who successfully exploited the vulnerability could elevate privileges.</p> <p>To exploit this vulnerability, an attacker would need to convince a user to open a specially crafted file.</p> <p>The security update addresses the vulnerability by correcting how Microsoft Office Click-to-Run (C2R) components handle these files.</p>

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Office: 2013, 2019
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Office 2013 Click-to-Run (C2R): from 15.0.0.0 before 15.0.5571.1000 — fixed in 15.0.5571.1000
• Microsoft Office: from 19.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Office 2013 Click-to-Run (C2R) 15.0.5571.1000; Microsoft Office https://aka.ms/OfficeSecurityReleases. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16955
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16955

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