Vulnerability Description
GitHub MCP Server is GitHub's official MCP Server. Prior to 1.1.0, the CompletionsHandler function in pkg/github/server.go accesses params.Ref without first checking whether it is nil, so a completion/complete request with a missing or empty ref field triggers a nil pointer dereference and a Go runtime panic; because the crash occurs before any authentication or token validation, any unauthenticated client able to send JSON-RPC messages can crash the server, resulting in a complete denial of service. This issue is fixed in version 1.1.0.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Github | Mcp Server | < 1.1.0 |
Related Weaknesses (CWE)
References
- https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee6Patch
- https://github.com/github/github-mcp-server/pull/2502Issue TrackingPatch
- https://github.com/github/github-mcp-server/releases/tag/v1.1.0Release Notes
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4ExploitVendor Advisory
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4ExploitVendor Advisory
FAQ
What is CVE-2026-47427?
CVE-2026-47427 is a vulnerability with a CVSS score of 7.5 (HIGH). GitHub MCP Server is GitHub's official MCP Server. Prior to 1.1.0, the CompletionsHandler function in pkg/github/server.go accesses params.Ref without first checking whether it is nil, so a completion...
How severe is CVE-2026-47427?
CVE-2026-47427 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-47427?
Check the references section above for vendor advisories and patch information. Affected products include: Github Mcp Server.