CVE-2026-50517: Microsoft 365 Copilot

Critical severity, CVSS 9.9. EPSS: 1.7% chance of exploitation in the next 30 days.

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

Affected products

• Microsoft 365 Copilot: affected versions not specified

Published 2026-07-24. Last modified 2026-07-29.