Vulnerability Report

CVE-2026-47427

Title: Nil Pointer Dereference in GitHub MCP Server

Memory Corruption

Proof Of Concept

No public PoC currently indexed for CVE-2026-47427.

CWE Category CWE-476

Published Date Jul 28, 2026

Modified Date Aug 08, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.41%

Vulnerability Summary

CVE-2026-47427: 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.

Impacted Vendors

litmus 1

github 1

Reference Links

https://github.com/github/github-mcp-server/commit/c88d2ecdd3bb07f7bdd75296e3ee676febf14f58 https://github.com/github/github-mcp-server/pull/2502 https://github.com/github/github-mcp-server/releases/tag/v1.1.0 https://github.com/github/github-mcp-server/security/advisories/GHSA-w4q6-qw23-4rg7

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns