CVE-2026-47427: CWE-476: NULL Pointer Dereference in github github-mcp-server
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.
AI Analysis
Technical Summary
CVE-2026-47427 is a NULL pointer dereference vulnerability (CWE-476) in the GitHub MCP Server's CompletionsHandler function located in pkg/github/server.go. Before version 1.1.0, the function accesses params.Ref without verifying if it is nil. If a JSON-RPC request omits or leaves the ref field empty, this triggers a nil pointer dereference leading to a Go runtime panic and server crash. The crash occurs before any authentication or token validation, enabling any unauthenticated client able to send JSON-RPC messages to cause a denial of service. The vulnerability is resolved in version 1.1.0.
Potential Impact
An attacker can send a specially crafted JSON-RPC request with a missing or empty ref field to cause the server to crash, resulting in a complete denial of service. There is no confidentiality or integrity impact. The vulnerability can be exploited remotely without authentication.
Mitigation Recommendations
Upgrade to GitHub MCP Server version 1.1.0 or later, where this NULL pointer dereference issue is fixed. Patch status is not explicitly confirmed in the advisory, but the fix is stated to be in version 1.1.0. Until upgraded, the server is vulnerable to denial of service from unauthenticated requests.
CVE-2026-47427: CWE-476: NULL Pointer Dereference in github github-mcp-server
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.
CVSS v3.1
Score 7.5high
Affected software
github
github-mcp-server
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-47427 is a NULL pointer dereference vulnerability (CWE-476) in the GitHub MCP Server's CompletionsHandler function located in pkg/github/server.go. Before version 1.1.0, the function accesses params.Ref without verifying if it is nil. If a JSON-RPC request omits or leaves the ref field empty, this triggers a nil pointer dereference leading to a Go runtime panic and server crash. The crash occurs before any authentication or token validation, enabling any unauthenticated client able to send JSON-RPC messages to cause a denial of service. The vulnerability is resolved in version 1.1.0.
Potential Impact
An attacker can send a specially crafted JSON-RPC request with a missing or empty ref field to cause the server to crash, resulting in a complete denial of service. There is no confidentiality or integrity impact. The vulnerability can be exploited remotely without authentication.
Mitigation Recommendations
Upgrade to GitHub MCP Server version 1.1.0 or later, where this NULL pointer dereference issue is fixed. Patch status is not explicitly confirmed in the advisory, but the fix is stated to be in version 1.1.0. Until upgraded, the server is vulnerable to denial of service from unauthenticated requests.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-19T19:37:43.527Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a68d75f9c2644c7f8e050a5
Added to database: 07/28/2026, 16:22:55 UTC
Last enriched: 07/29/2026, 16:53:06 UTC
Last updated: 09/12/2026, 10:01:31 UTC
Views: 62
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