{"schemaVersion":3,"id":"CVE-2026-47427","aliases":["GHSA-w4q6-qw23-4rg7","GO-2026-6118"],"status":"published","duplicateOf":null,"title":null,"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. 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