CVE-2026-47427

GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler

Published Jul 28, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-w4q6-qw23-4rg7 GitHub MCP Server has Nil Pointer Dereference DoS in completion/complete Handler
History
Type Values Removed Values Added
First Time appeared Github
Github github-mcp-server
Vendors & Products Github
Github github-mcp-server
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title GitHub MCP Server: Nil Pointer Dereference DoS in completion/complete Handler
Weaknesses CWE-476
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 28, 2026, 5:31 PM
Reserved
May 19, 2026, 7:37 PM
Status
Analyzed
Published
Jul 28, 2026, 4:18 PM
Modified
Oct 24, 2026, 1:10 PM