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CVE-2025-66389

7.5 · HIGH
Published Jun 22, 2026 microsoft CWE-552

Overview

CVE-2025-66389 is a high-severity vulnerability affecting microsoft github_copilot. It was published on June 22, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical Description

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.

Remediation

Check the references section for vendor advisories and patches from microsoft. Update github_copilot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

Vendor Product Versions Status

References

Ref blindcyber.com/2025/10/28/copilot-fun/ GitHub github.com/microsoft/vscode-copilot-chat/ GitHub github.com/microsoft/vscode/blob/03baef1008086ed4960042fa463e570072173bb5/src/vs/workbench/contrib/chat/electron-browser/tools/fetchPageTool.ts#L152

Frequently Asked Questions

What is CVE-2025-66389?

CVE-2025-66389 is a high-severity vulnerability affecting microsoft github_copilot. It was published on June 22, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2025-66389?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2025-66389?

Check the references section for vendor advisories and patches from microsoft. Update github_copilot to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2025-66389?

CyberStrike's AI-powered security agents can automatically detect CVE-2025-66389 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.

How CyberStrike Helps

Autonomous Discovery

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Continuous Pentesting

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Code Review

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HackBrowser

Browser-based exploitation validates findings with real proof-of-concept.
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