PatchSiren cyber security CVE debrief
CVE-2025-66389 GitHub CVE debrief
CVE-2025-66389 is a vulnerability in GitHub Copilot 1.372.0 that allows filesystem access outside of a workspace folder without user approval. This occurs via a file-handler URI parameter to fetch_webpage, potentially leading to exfiltration if there is indirect prompt injection. The CVE was published on June 22, 2026. Affected users should review and update their installations to mitigate potential risks. This issue has a significant impact on the security posture of users relying on GitHub Copilot, emphasizing the need for careful configuration and monitoring.
- Vendor
- GitHub
- Product
- Copilot
- CVSS
- Unknown
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-06-22
- Original CVE updated
- 2026-06-22
- Advisory published
- 2026-06-22
- Advisory updated
- 2026-06-22
Who should care
Developers and organizations using GitHub Copilot 1.372.0 should be aware of this vulnerability. Given the potential for exfiltration, it is crucial for users to assess their exposure and take necessary precautions to secure their environments. This includes reviewing GitHub Copilot configurations, ensuring that it is properly secured, and monitoring for any suspicious activities.
Technical summary
The vulnerability in GitHub Copilot 1.372.0 arises from its handling of file-handler URI parameters in the fetch_webpage function. This allows for filesystem access outside of the designated workspace folder without requiring user approval. The issue is significant as it could enable indirect prompt injection attacks, leading to potential data exfiltration. Users should verify their version and apply any available patches or mitigations.
Defensive priority
High priority due to potential for data exfiltration
Recommended defensive actions
- Review and update GitHub Copilot installations to the latest version
- Configure GitHub Copilot to restrict filesystem access to workspace folders only
- Monitor GitHub Copilot usage for suspicious activities
- Implement additional security measures to detect and prevent indirect prompt injection attacks
- Consult official GitHub documentation and security advisories for further guidance
Evidence notes
The CVE-2025-66389 record indicates that GitHub Copilot 1.372.0 is vulnerable to filesystem access outside of a workspace folder. Evidence from the source item (nvd_modified) and references (blindcyber.com, github.com/microsoft/vscode-copilot-chat, github.com/microsoft/vscode) supports this finding. Users should verify their GitHub Copilot version and review configurations to ensure security.
Official resources
This article is AI-assisted and based on the supplied source corpus.