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Microsoft Security Response CenterCVE-2026-26164

M365 Copilot Information Disclosure Vulnerability

CriticalVendor CVSS 7.5 / 10 1 CVE Published May 7, 2026 at 7:00 AM UTC

Summary

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

Products covered

  • Microsoft 365 Copilot's Business Chat

Remediation

Separate remediation guidance was not included in the collected bulletin.

CVEs in this advisory 1

Updates

  1. Published by Microsoft Security Response Center

    The publication date reported by the vendor.

  2. Added to SecurityAlert

    We collected the advisory from the official source.

  3. Confirmed at the source

    Our collector saw this advisory during a later source check.