CVE-2021-43905 Microsoft Office app Remote Code Execution Vulnerability
Attackers can execute arbitrary code on systems running the Microsoft Office app, requiring immediate patching by users and administrators.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-43905?
CVE-2021-43905 is a critical code injection vulnerability in Microsoft 365 Copilot, published on 15 Dec 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Microsoft Office app Remote Code Execution Vulnerability
Which versions are affected by CVE-2021-43905?
It affects 1 product.
Products include Microsoft 365 Copilot.
How do I fix CVE-2021-43905?
No fix has been published for CVE-2021-43905 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2021-43905 being exploited?
There is no known exploitation of CVE-2021-43905 in the wild and no public exploit code.
Other vulnerabilities in Microsoft 365 Copilot
- CVE-2026-85885 Microsoft 365 Copilot Elevation of Privilege Vulnerability
- CVE-2026-50517 Microsoft M365 Copilot Remote Code Execution Vulnerability
- CVE-2026-54130 M365 Copilot Information Disclosure Vulnerability
- CVE-2025-60724 GDI+ Remote Code Execution Vulnerability
- CVE-2025-53766 GDI+ Remote Code Execution Vulnerability
Sources
Also known as GHSA-p5c8-x5qh-v2mv.