What is CVE-2026-21518?

CVE-2026-21518 is a high-severity vulnerability in Microsoft Visual Studio Code Copilot Chat Extension, classified under Command Injection. CVSS score: 8.8/10. Published 2026-02-10.

How severe is CVE-2026-21518?

High severity. CVSS v3 base score is 8.8 out of 10.

RCE in Microsoft Visual Studio Code Copilot Chat Extension

CVE-2026-21518

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

Vulnerability class: Command Injection (OS Command Injection)

EPSS: 0.001 (21.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). 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.

Affected products

Microsoft Visual Studio Code Copilot Chat Extension — versions 0.27.0
Microsoft Visual Studio Code — versions 1.0.0

Weakness classification (CWE)

CWE-77 — Command Injection

References

GitHub Copilot and Visual Studio Code Security Feature Bypass Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-21518?: CVE-2026-21518 is a high-severity vulnerability in Microsoft Visual Studio Code Copilot Chat Extension, classified under Command Injection. CVSS score: 8.8/10. Published 2026-02-10.
How severe is CVE-2026-21518?: High severity. CVSS v3 base score is 8.8 out of 10.