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CVE-2026-41090: Microsoft Copilot Command Injection Vulnerability

CVE-2026-41090 is a command injection vulnerability in Microsoft Copilot, allowing an unauthorized attacker to perform tampering over a network.

CVE-2026-41090 is a critical command injection vulnerability affecting Microsoft Copilot. This flaw allows an attacker to inject arbitrary commands, potentially leading to unauthorized tampering over a network. The vulnerability stems from improper neutralization of special elements used in commands. Successful exploitation could grant an attacker significant control over the affected system. This vulnerability was published on 2026-05-22. This poses a significant risk to organizations utilizing Microsoft Copilot, as it can lead to data breaches, system compromise, and further malicious activities within the network.

Attack Chain

  1. Attacker crafts a malicious input containing special elements (e.g., shell metacharacters) designed for command injection.
  2. The malicious input is submitted to Microsoft Copilot via network communication.
  3. Copilot processes the input without proper neutralization of the special elements.
  4. The injected command is executed by the underlying operating system or application server.
  5. The attacker leverages the command execution to perform unauthorized actions, such as reading sensitive data.
  6. Attacker modifies system configurations or data, leading to tampering.
  7. The attacker escalates privileges by exploiting the command injection vulnerability.
  8. The attacker uses compromised Copilot instance as pivot to move laterally within the network.

Impact

Successful exploitation of CVE-2026-41090 allows an attacker to perform unauthorized tampering over a network. This can lead to data breaches, system compromise, and potentially complete control over the affected Microsoft Copilot instance. The CVSS v3.1 base score is 9.3, highlighting the critical severity of this vulnerability.

Recommendation

  • Apply the patch provided by Microsoft as detailed in the MSRC advisory https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-41090.
  • Deploy the Sigma rule “Detects CVE-2026-41090 Exploitation – Suspicious Copilot Command” to detect potential exploitation attempts.
  • Monitor network traffic for suspicious commands being sent to Microsoft Copilot using network connection logs.
  • Enable logging of all commands executed by the Copilot application and review for any anomalies.

Detection coverage 2

Detects CVE-2026-41090 Exploitation -- Suspicious Copilot Command

high

Detects CVE-2026-41090 exploitation -- execution of suspicious commands by Microsoft Copilot indicating command injection

sigma tactics: execution techniques: T1059.004 sources: process_creation, windows

Detects CVE-2026-41090 Exploitation -- Copilot Network Connection to Suspicious Port

medium

Detects CVE-2026-41090 exploitation -- Microsoft Copilot making network connection to a suspicious port after command injection

sigma tactics: command_and_control techniques: T1071.001 sources: network_connection, windows

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