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Vulnerability record · CVE-2021-43905 · published 15 December 2021
CVE-2021-43905: Microsoft 365 copilot vulnerability
Microsoft · 365 Copilot
Microsoft Office app Remote Code Execution Vulnerability
9.6 CVSS 3.1 Critical EPSS 2.8% · top 14.0%
9.6CVSS 3.1 base score, v2 6.8
2.8%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD
Description
Microsoft Office app Remote Code Execution Vulnerability
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905 | PatchVendor Advisory |
| https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905 | PatchVendor Advisory |
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
9.9CVE-2026-50517Microsoft 365 copilot deserialization of untrusted data vulnerabilityDeserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.EPSS 1.7%9.8CVE-2026-58617Microsoft 365 copilot improper access control vulnerabilityImproper access control in Microsoft 365 Copilot for iOS allows an unauthorized attacker to elevate privileges over a network.EPSS 0.79%9.8CVE-2025-60724Microsoft 365 copilot heap-based buffer overflow vulnerabilityHeap-based buffer overflow in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.EPSS 5.9%9.8CVE-2025-53766Microsoft 365 copilot heap-based buffer overflow vulnerabilityHeap-based buffer overflow in Windows GDI+ allows an unauthorized attacker to execute code over a network.EPSS 8.0%9.6CVE-2026-48561Microsoft 365 copilot command injection vulnerabilityImproper neutralization of special elements used in a command ('command injection') in Copilot Chat (Microsoft Edge) allows an unauthorized attacker …EPSS 0.86%9.3CVE-2026-41106Microsoft 365 copilot open redirect vulnerabilityUrl redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate privileges over a network.EPSS 0.72%9.3CVE-2026-41090Microsoft 365 copilot command injection vulnerabilityImproper neutralization of special elements used in a command ('command injection') in Microsoft Copilot allows an unauthorized attacker to perform t…EPSS 0.76%9.3CVE-2026-33102Microsoft 365 copilot open redirect vulnerabilityUrl redirection to untrusted site ('open redirect') in M365 Copilot allows an unauthorized attacker to elevate privileges over a network.EPSS 0.72%
Source: NIST National Vulnerability Database (record CVE-2021-43905), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
