CVE-2026-63118

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a locally running MCP server and invoke exposed tools. This issue is fixed in version 0.23.0.

CVSS

No CVSS.

References

Link	Resource
https://github.com/modelcontextprotocol/ruby-sdk/commit/ba543083a7594e7892b29464b89091816446ff7a
https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m

Configurations

No configuration.

History

24 Oct 2026, 13:10

Type	Values Removed	Values Added
Summary		(es) MCP Ruby SDK es el SDK oficial de Ruby para servidores y clientes del Protocolo de Contexto de Modelo. Antes de la versión 0.23.0, MCP::Server::Transports::StreamableHTTPTransport en la gema mcp no valida los encabezados de solicitud HTTP Host u Origin, lo que permite a una página de navegador maliciosa utilizar la revinculación de DNS para alcanzar un servidor MCP que se ejecuta localmente e invocar herramientas expuestas. Este problema se corrige en la versión 0.23.0.

Information

Published : 2026-07-29 20:17

Updated : 2026-10-24 13:10

NVD link : CVE-2026-63118

Mitre link : CVE-2026-63118

CVE.ORG link : CVE-2026-63118

JSON object : View

Products Affected

No product.

CWE

CWE-346

Origin Validation Error

CWE-350

Reliance on Reverse DNS Resolution for a Security-Critical Action

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