Microsoft 365 Word Copilot vulnerabilities

2 CVEs affecting Microsoft 365 Word Copilot, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2026-21521, published 2026-01-22.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2026-21521, published 2026-01-22. 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.
• CVE-2025-59252, published 2025-10-09. Critical severity, CVSS 9.3. EPSS: 0.6% chance of exploitation in the next 30 days. Improper neutralization of special elements used in a command ('command injection') in Copilot allows an unauthorized attacker to disclose information over a network.