{"id":"CVE-2026-47427","aliases":["GHSA-w4q6-qw23-4rg7","GO-2026-6118"],"url":"https://o3.security/vulnerability/CVE-2026-47427","summary":"GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler","details":"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.","published":"2026-07-28T15:32:27.294Z","modified":"2026-09-09T18:26:42.843133732Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00442,"percentile":0.37289,"asOf":"2026-09-13"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/github/github-mcp-server","fixedVersion":"1.1.0"}],"fix":{"url":"https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58","label":"github/github-mcp-server@c88d2ec"},"references":[{"type":"WEB","url":"https://github.com/github/github-mcp-server/releases/tag/v1.1.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47427.json"},{"type":"ADVISORY","url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47427"},{"type":"FIX","url":"https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58"},{"type":"FIX","url":"https://github.com/github/github-mcp-server/pull/2502"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-09T18:26:42.843133732Z"}}