{"id":"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.","aliases":["GHSA-w4q6-qw23-4rg7"],"modified":"2026-08-01T03:32:57.292523410Z","published":"2026-07-28T15:32:27.294Z","database_specific":{"cwe_ids":["CWE-476"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47427.json","cna_assigner":"GitHub_M"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/github/github-mcp-server","events":[{"introduced":"0"},{"fixed":"c88d2ecdd3bb07f7bdd75296e3ee676febf14f58"},{"fixed":"c5be4b09c2e26e9c6adbc936b5fc661306852ebf"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.1.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v1.0.5","v1.0.4","v1.0.3","v1.0.2","v1.0.1","v1.0.0","v0.33.1","v0.33.0","v0.32.0","v0.31.0","v0.30.3","v0.30.2","v0.30.1","v0.30.0","v0.29.0","v0.28.1","v0.28.0","v0.27.0","v0.26.3","v0.26.2","v0.26.1","v0.26.0","v0.25.0","v0.24.1","v0.24.0","v0.22.0","v0.23.0","v0.21.0","v0.20.2","v0.20.1","v0.20.0","v0.19.1","v0.19.0","v0.18.0","v0.17.1","v0.17.0","v0.16.0","v0.15.0","v0.13.0","v0.14.0","v0.12.1","v0.12.0","v0.11.0","v0.10.0","v0.9.1","v0.9.0","v0.8.0","v0.7.0","v0.6.0","v0.5.0","v0.4.0","v0.3.0","v0.2.1","v0.2.0","v0.1.1-release-validation","v0.1.1","v0.1.0","v0.1.0-rc.3","v0.1.0-rc.2","v0.1.0-rc.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-47427.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}