CVE-2026-47427: 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.
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H · CWE-476
Tracked companies
Mapped from the CVE’s affected-product data, NVD CPE matches, vendor advisories or package feeds. A mapping means the vendor’s software is named, not that its hosted service was exposed.
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
github: github-mcp-server
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14… (opens in new tab)
- github.com/github/github-mcp-server/pull/2502 (opens in new tab)
- github.com/github/github-mcp-server/releases/tag/v1.1.0 (opens in new tab)
- github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7 (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)