What’s Vulnerable › Vulnerabilities

CVE-2021-43905: Microsoft Office app Remote Code Execution Vulnerability

• Severity: critical (CVSS 9.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-12-15 · updated 2026-06-17

Description

Microsoft Office app Remote Code Execution Vulnerability

Affected products

• Microsoft 365 Copilot: before 18.2110.13110.0 — fixed in 18.2110.13110.0
• Microsoft Office app: before publication — fixed in publication

How to fix

Upgrade to a fixed version: Microsoft 365 Copilot 18.2110.13110.0; Microsoft Office app publication. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905

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