CVE-2026-21256: GitHub Copilot and Visual Studio Remote Code Execution Vulnerability

Overview

Severity

High (CVSS 8.8)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Remote Code Execution

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Feb

Released

2026-02-10

Last Updated

2026-03-13

EPSS Score

0.04% (percentile: 12.1%)

Description

Improper neutralization of special elements used in a command ('command injection') in GitHub Copilot and Visual Studio allows an unauthorized attacker to execute code over a network.

FAQ

How could an attacker exploit this vulnerability? The AV:N rating indicates the vulnerability is exploitable over the network, meaning an attacker can deliver a malicious prompt remotely without prior access, while UI:R means a user must interact with Copilot for exploitation to occur. Due to prompt injection, the system is coerced into executing attacker-controlled instructions, which can escalate into remote code execution (RCE) when the compromised prompt causes backend components or integrated tools to run unintended commands.

Affected Products (2)

Developer Tools

• Microsoft Visual Studio 2022 version 17.14
• Microsoft Visual Studio 2026 version 18.3

Security Updates (2)

• Release Notes
• Release Notes

Acknowledgments

<a href="https://www.linkedin.com/in/tarek-nakkouch/">Nakkouch Tarek</a>

Revision History

• 2026-02-10: Information published.
• 2026-02-11: Changes made to the security updates links and information. This is an informational change only.
• 2026-03-13: Changes made to the security updates links and information. This is an informational change only.