{"id":"CVE-2026-47427","state":"PUBLISHED","title":"GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler","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.","publishedAt":"2026-07-28T15:32:27.294Z","updatedAt":"2026-07-28T17:31:19.108Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["github github-mcp-server"],"affected":[{"vendor":"github","product":"github-mcp-server","versions":[{"version":"< 1.1.0","status":"affected"}]}],"references":["https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7","https://github.com/github/github-mcp-server/pull/2502","https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58","https://github.com/github/github-mcp-server/releases/tag/v1.1.0"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/47xxx/CVE-2026-47427.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47427","state":"PUBLISHED","datePublished":"2026-07-28T15:32:27.294Z","dateUpdated":"2026-07-28T17:31:19.108Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-05-19T19:37:43.527Z"},"containers":{"cna":{"title":"GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler","descriptions":[{"lang":"en","value":"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":[{"vendor":"github","product":"github-mcp-server","versions":[{"version":"< 1.1.0","status":"affected"}]}],"references":[{"url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7","name":"https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/github/github-mcp-server/pull/2502","name":"https://github.com/github/github-mcp-server/pull/2502","tags":["x_refsource_MISC"]},{"url":"https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58","name":"https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58","tags":["x_refsource_MISC"]},{"url":"https://github.com/github/github-mcp-server/releases/tag/v1.1.0","name":"https://github.com/github/github-mcp-server/releases/tag/v1.1.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","description":"CWE-476: NULL Pointer Dereference","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-28T15:32:27.294Z"},"source":{"advisory":"GHSA-w4q6-qw23-4rg7","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-28T17:31:12.371732Z","id":"CVE-2026-47427","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-28T17:31:19.108Z"}}]}}}