high7.5
CVE-2026-47427
GitHub MCP Server has Nil Pointer Dereference DoS in completion/complete Handler
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/github/github-mcp-server | < 1.1.0 | 1.1.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Github | Mcp Server | before 1.1.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-w4q6-qw23-4rg7
- 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