CVE-2026-50517 Microsoft M365 Copilot Remote Code Execution Vulnerability
An authorized attacker can execute arbitrary code remotely via unsafe deserialization in Microsoft 365 Copilot.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-50517?
CVE-2026-50517 is a critical unsafe deserialization vulnerability in Microsoft 365 Copilot, published on 24 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.
Weakness: CWE-502
Which versions are affected by CVE-2026-50517?
It affects 1 product.
Products include Microsoft 365 Copilot.
How do I fix CVE-2026-50517?
No fix has been published for CVE-2026-50517 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-50517 being exploited?
There is no known exploitation of CVE-2026-50517 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-2026-54130 M365 Copilot Information Disclosure Vulnerability
- CVE-2025-60724 GDI+ Remote Code Execution Vulnerability
- CVE-2025-53766 GDI+ Remote Code Execution Vulnerability
- CVE-2026-48561 Microsoft Edge Copilot Remote Code Execution Vulnerability
Sources
Also known as GHSA-cfm3-7vpc-px47.