CVE-2026-47427: GitHub Mcp Server

High severity, CVSS 7.5. EPSS: 0.8% chance of exploitation in the next 30 days.

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.

Affected products

• GitHub Mcp Server: before 1.1.0 (fixed in 1.1.0)

Published 2026-07-28. Last modified 2026-08-08.