CVE-2026-26164: Microsoft 365 Copilot Chat

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Copilot Chat: affected versions not specified

Published 2026-05-07. Last modified 2026-06-17.