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CRITICAL · 9.9

CVE-2026-50517

Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

Vulnerability Description

Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

CVSS Score

9.9

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
Microsoft365 Copilot-

Related Weaknesses (CWE)

CWE-502

References

FAQ

What is CVE-2026-50517?

CVE-2026-50517 is a vulnerability with a CVSS score of 9.9 (CRITICAL). Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

How severe is CVE-2026-50517?

CVE-2026-50517 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-50517?

Check the references section above for vendor advisories and patch information. Affected products include: Microsoft 365 Copilot.