A command injection vulnerability in Microsoft Copilot allows an unauthenticated attacker to tamper with the service over a network, without requiring any user interaction or elevated privileges. The flaw stems from improper handling of special characters within commands, a class of vulnerability that can enable attackers to manipulate application behaviour or underlying systems. Given Copilot’s integration across Microsoft 365 and Azure services, the potential blast radius for affected organisations is significant.

Security Architect’s Take: Review your organisation’s exposure to Microsoft Copilot endpoints and ensure network-level controls restrict access to trusted users only; monitor Microsoft’s remediation guidance closely and apply any available patches or mitigations immediately, particularly if Copilot is integrated with sensitive data sources or enterprise workflows.

Original advisory: CVE-2026-42895 Microsoft Copilot Tampering Vulnerability