Github Copilot: Files or Directories Accessible to External Parties
CVE-2025-66389 is a high-severity files or directories accessible to external parties vulnerability in Github Copilot from Microsoft, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Github Copilot versions: 1.372.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.18% chance of exploitation within 30 days, higher than 68% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Github Copilot you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Github Copilot | 1.372.0 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CISA (ADP).
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Files or Directories Accessible to External Parties
The product makes files or directories accessible to unauthorized actors, even though they should not be.
How developers prevent this class of flaw
- When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to disable public access.
More Files or Directories Accessible to External Parties vulnerabilities (CWE-552)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- blindcyber.com/2025/10/28/copilot-fun/Exploit, Third Party Advisory
Other references
Other vulnerabilities in Github Copilot
- 7.8 High severity
- 7.8 High severity
Recent Files or Directories Accessible to External Parties vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.7 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.5 High severity
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