CVE-2026-78501: Microsoft 365 Copilot Chat

High severity, CVSS 8.6. EPSS: 0.5% chance of exploitation in the next 30 days.

Improper neutralization of special elements used in a command ('command injection') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Copilot Chat: affected versions not specified

Published 2026-09-17. Last modified 2026-10-07.