{"id":"CVE-2026-42559","revision":"64b63a7725474c20a816143addc4ca1c","records":[{"revision":"64b63a7725474c20a816143addc4ca1c","observedAt":"2026-10-27T11:12:04.713+00:00","statement":{"source":"nvd","id":"CVE-2026-42559","aliases":[],"title":"RMCP is an official Rust SDK for the Model Context Protocol. Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport (crates/rmcp/src/transport/streamable_http_server/) did not validate the incoming Host header. This allow…","description":"RMCP is an official Rust SDK for the Model Context Protocol. Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport (crates/rmcp/src/transport/streamable_http_server/) did not validate the incoming Host header. This allowed a malicious public website, via a DNS rebinding attack, to send authenticated requests to an MCP server running on the victim's loopback or private-network interface. This vulnerability is fixed in 1.4.0.","state":0,"publishedAt":"2026-05-14T15:16:46.75+00:00","modifiedAt":"2026-10-26T14:10:00.13+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://github.com/modelcontextprotocol/rust-sdk/commit/8e22aa2de28df5a285eed87c11cd89bf15fa90d3","https://github.com/modelcontextprotocol/rust-sdk/issues/815","https://github.com/modelcontextprotocol/rust-sdk/issues/822","https://github.com/modelcontextprotocol/rust-sdk/pull/764","https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-x53w-74fx"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-42559","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-346","CWE-350"],"productCriteria":[],"sourceDates":{"published":"2026-05-14T15:16:46.750","lastModified":"2026-10-26T14:10:00.130"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-42559","identifiers":["CVE-2026-42559"]},"retained":false,"historicalAffected":[]}],"coverage":[]}