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.
Affected products
github: mcp server
References5
- github.com/github/github-mcp-server/security/advisories/GHSA-w4… ExploitVendor Advisory
- github.com/github/github-mcp-server/security/advisories/GHSA-w4… ExploitVendor Advisory
- github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd7… Patch
- github.com/github/github-mcp-server/pull/2502 Issue TrackingPatch
- github.com/github/github-mcp-server/releases/tag/v1.1.0 Release Notes
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 56 · as of 13 November 2026
- CWE
- CWE-476
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