GitHub Copilot 1.372.0 allows filesystem access outside of a workspace folder (without user approval) via a file-handler URI parameter to fetch_webpage.
Date: 2026-06
Affected: microsoft/github_copilot
Attack vector: prompt-injection
Category: vulnerability-disclosure
Severity: High
CVE: CVE-2025-66389
CWE: CWE-552
CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

GitHub Copilot 1.372.0 allows filesystem access outside of a workspace folder (without user approval) via a file-handler URI parameter to fetch_webpage. Therefore, exfiltration could occur if there is indirect prompt injection.


Mitigations:

Architectural layers (MAESTRO):