CVE-2021-43905

Name: CVE-2021-43905
Creator: NVD / NIST
Published: 2021-12-15T15:15:11.467+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.6/10EPSS 2.82%

Last modified Jun 17, 2026

CVE-2021-43905 is a critical-severity vulnerability rated 9.6/10 on the CVSS scale. Microsoft Office app Remote Code Execution Vulnerability. EPSS estimates a 2.82% chance of exploitation in the next 30 days.

Description

Microsoft Office app Remote Code Execution Vulnerability

Metrics

CVSS 3.1

9.6/10

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

EPSS Probability

2.82%

84.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Microsoft	365 Copilot	< 18.2110.13110.0

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905Patch, Vendor Advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905Patch, Vendor Advisory

Timeline

Published: Dec 15, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-43905?

Microsoft Office app Remote Code Execution Vulnerability

How severe is CVE-2021-43905?

CVE-2021-43905 has a CVSS score of 9.6/10 (CRITICAL severity). The EPSS model estimates a 2.82% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43905?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-43905?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST