{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42559","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-04-28T16:56:50.192Z","datePublished":"2026-05-14T14:24:56.090Z","dateUpdated":"2026-05-14T16:00:33.149Z"},"containers":{"cna":{"title":"RMCP: DNS rebinding vulnerability in rmcp Streamable HTTP server transport","problemTypes":[{"descriptions":[{"cweId":"CWE-346","lang":"en","description":"CWE-346: Origin Validation Error","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-350","lang":"en","description":"CWE-350: Reliance on Reverse DNS Resolution for a Security-Critical Action","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-x53w-74fx","tags":["x_refsource_CONFIRM"],"url":"https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-x53w-74fx"},{"name":"https://github.com/modelcontextprotocol/rust-sdk/issues/815","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/rust-sdk/issues/815"},{"name":"https://github.com/modelcontextprotocol/rust-sdk/issues/822","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/rust-sdk/issues/822"},{"name":"https://github.com/modelcontextprotocol/rust-sdk/pull/764","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/rust-sdk/pull/764"},{"name":"https://github.com/modelcontextprotocol/rust-sdk/commit/8e22aa2de28df5a285eed87c11cd89bf15fa90d3","tags":["x_refsource_MISC"],"url":"https://github.com/modelcontextprotocol/rust-sdk/commit/8e22aa2de28df5a285eed87c11cd89bf15fa90d3"}],"affected":[{"vendor":"modelcontextprotocol","product":"rust-sdk","versions":[{"version":"< 1.4.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-05-14T14:24:56.090Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-89vp-x53w-74fx","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-14T16:00:22.834947Z","id":"CVE-2026-42559","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-14T16:00:33.149Z"}}]}}