CVE-2026-21521: Microsoft 365 Word Copilot

High severity, CVSS 7.4. EPSS: 0.6% chance of exploitation in the next 30 days.

Improper neutralization of escape, meta, or control sequences in Copilot allows an unauthorized attacker to disclose information over a network.

Affected products

• Microsoft 365 Word Copilot: affected versions not specified

Published 2026-01-22. Last modified 2026-06-17.