cvedb.io
CVE-2026-34742
HIGH · CVSS 8.1
EPSS exploitation probability: 0%
Published 2026-04-02T19:21:33.023 · Last modified 2026-06-30T03:18:57.460

Summary

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.0, the Model Context Protocol (MCP) Go 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 StreamableHTTPHandler or SSEHandler, 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. This issue has been patched in version 1.4.0.

Affected products

lfprojects — mcp_go_sdk

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.