CVE-2026-21523: GitHub Copilot and Visual Studio Code Remote Code Execution Vulnerability

Overview

Severity
High (CVSS 8)
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/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
2026-02-27
EPSS Score
0.03% (percentile: 10.4%)

Description

Time-of-check time-of-use (toctou) race condition in GitHub Copilot and Visual Studio allows an authorized 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 Code CoPilot Chat Extension
  • Visual Studio Code

Security Updates (2)

Acknowledgments

Anonymous, Alexander Tan

Revision History

  • 2026-02-10: Information published.
  • 2026-02-27: Download links fixed