CVE-2025-66414

High

Description

MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. Prior to 1.24.0, The Model Context Protocol (MCP) TypeScript SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication with StreamableHTTPServerTransport or SSEServerTransport and has not enabled enableDnsRebindingProtection, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.24.0.

SeverityHigh
CVSS8.1
Exploit probability—
ProductLfprojects Mcp Typescript Sdk
PublishedDec 2, 2025
First seenDec 2, 2025
Weakness typeCWE-1188CWE-1188

How to fix

Update
  • lfprojects mcp_typescript_sdk1.24.0 or later
  • @modelcontextprotocol/sdk1.24.0 or later

Affected products

ProductAffected versionsFixed in
lfprojects mcp_typescript_sdkv < 1.24.01.24.0
@modelcontextprotocol/sdknpmv < 1.24.01.24.0

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