Vulnerability Details CVE-2026-47427
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 33.8%
CVSS Severity
CVSS v3 Score 7.5
References
- https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58
- https://github.com/github/github-mcp-server/pull/2502
- https://github.com/github/github-mcp-server/releases/tag/v1.1.0
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7
- https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7
Products affected by CVE-2026-47427
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cpe:2.3:a:github:mcp_server:0.1.0
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cpe:2.3:a:github:mcp_server:0.1.1
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cpe:2.3:a:github:mcp_server:0.10.0
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cpe:2.3:a:github:mcp_server:0.11.0
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cpe:2.3:a:github:mcp_server:0.12.0
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cpe:2.3:a:github:mcp_server:0.12.1
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cpe:2.3:a:github:mcp_server:0.13.0
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cpe:2.3:a:github:mcp_server:0.14.0
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cpe:2.3:a:github:mcp_server:0.15.0
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cpe:2.3:a:github:mcp_server:0.16.0
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cpe:2.3:a:github:mcp_server:0.17.0
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cpe:2.3:a:github:mcp_server:0.17.1
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cpe:2.3:a:github:mcp_server:0.18.0
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cpe:2.3:a:github:mcp_server:0.19.0
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cpe:2.3:a:github:mcp_server:0.19.1
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cpe:2.3:a:github:mcp_server:0.2.0
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cpe:2.3:a:github:mcp_server:0.2.1
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cpe:2.3:a:github:mcp_server:0.20.0
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cpe:2.3:a:github:mcp_server:0.20.1
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cpe:2.3:a:github:mcp_server:0.20.2
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cpe:2.3:a:github:mcp_server:0.21.0
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cpe:2.3:a:github:mcp_server:0.22.0
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cpe:2.3:a:github:mcp_server:0.23.0
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cpe:2.3:a:github:mcp_server:0.24.0
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cpe:2.3:a:github:mcp_server:0.24.1
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cpe:2.3:a:github:mcp_server:0.25.0
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cpe:2.3:a:github:mcp_server:0.26.0
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cpe:2.3:a:github:mcp_server:0.26.1
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cpe:2.3:a:github:mcp_server:0.26.2
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cpe:2.3:a:github:mcp_server:0.26.3
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cpe:2.3:a:github:mcp_server:0.27.0
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cpe:2.3:a:github:mcp_server:0.28.0
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cpe:2.3:a:github:mcp_server:0.28.1
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cpe:2.3:a:github:mcp_server:0.29.0
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cpe:2.3:a:github:mcp_server:0.3.0
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cpe:2.3:a:github:mcp_server:0.30.0
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cpe:2.3:a:github:mcp_server:0.30.1
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cpe:2.3:a:github:mcp_server:0.30.2
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cpe:2.3:a:github:mcp_server:0.30.3
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cpe:2.3:a:github:mcp_server:0.31.0
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cpe:2.3:a:github:mcp_server:0.32.0
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cpe:2.3:a:github:mcp_server:0.33.0
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cpe:2.3:a:github:mcp_server:0.33.1
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cpe:2.3:a:github:mcp_server:0.4.0
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cpe:2.3:a:github:mcp_server:0.5.0
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cpe:2.3:a:github:mcp_server:0.6.0
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cpe:2.3:a:github:mcp_server:0.7.0
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cpe:2.3:a:github:mcp_server:0.8.0
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cpe:2.3:a:github:mcp_server:0.9.0
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cpe:2.3:a:github:mcp_server:0.9.1
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cpe:2.3:a:github:mcp_server:1.0.0
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cpe:2.3:a:github:mcp_server:1.0.1
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cpe:2.3:a:github:mcp_server:1.0.2
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cpe:2.3:a:github:mcp_server:1.0.3
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cpe:2.3:a:github:mcp_server:1.0.4
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cpe:2.3:a:github:mcp_server:1.0.5