File Access Vulnerability in GitHub Copilot by Microsoft
CVE-2025-66389

7.5HIGH

Key Information:

Vendor

Microsoft
Status
GitHub Copilot
Vendor
CVE Published:
22 June 2026

What is CVE-2025-66389?

In GitHub Copilot version 1.372.0, a security flaw allows unauthorized filesystem access beyond the designated workspace folder via a file-handler URI parameter in the fetch_webpage tool. This could lead to potential exfiltration of sensitive information due to indirect prompt injection, posing a risk to users' data integrity.

References

https://github.com/microsoft/vscode-copilot-chat/
https://github.com/microsoft/vscode/blob/03baef1008086ed4...
https://blindcyber.com/2025/10/28/copilot-fun/

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.