{"id":"EUVD-2026-81266","revision":"9c62cbb0773d48c083ff1deebc368c7d","records":[{"revision":"9c62cbb0773d48c083ff1deebc368c7d","observedAt":"2026-11-09T14:14:20.381+00:00","statement":{"source":"euvd","id":"EUVD-2026-81266","aliases":["CVE-2026-64684","GHSA-9g45-5xwm-f3wc"],"title":"RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.1.0, the rmcp crate's StreamableHttpClientTransport in crates/rmcp/src/transport/common/reqwest/streamable_http_client.rs builds its default_http_client with reqwest's …","description":"RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.1.0, the rmcp crate's StreamableHttpClientTransport in crates/rmcp/src/transport/common/reqwest/streamable_http_client.rs builds its default_http_client with reqwest's automatic redirect policy and applies caller-supplied values from StreamableHttpClientTransportConfig.custom_headers without marking them as sensitive. When a malicious or compromised MCP endpoint returns a cross-origin 307 or 308 redirect, reqwest follows the redirect and apply_custom_headers causes custom API keys or authentication tokens to be replayed to the new origin, where an attacker can capture and reuse them. The separate auth_header path is not affected because it uses the standard Authorization header, which reqwest strips on cross-origin redirects. This issue is fixed in version 2.1.0.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N","score":6.8,"severity":null}],"references":["https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-9g45-5xwm-f3wc","https://github.com/modelcontextprotocol/rust-sdk/pull/936","https://github.com/modelcontextprotocol/rust-sdk/commit/496902b9cf2c8a947454718da31829ae776b969b","https://github.com/modelcontextprotocol/rust-sdk/releases/tag/rmcp-v2.1.0"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-81266","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Sep 16, 2026, 9:18:48 PM","dateUpdated":"Sep 19, 2026, 1:56:51 AM"},"relatedAdvisories":[{"id":"openSUSE-SU-2026:11849-1","title":"openai-codex-0.155.1-1.1 on GA media","vulnerabilityIds":["CVE-2026-63127","CVE-2026-63128","CVE-2026-64684"]}],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-81266","identifiers":["EUVD-2026-81266","CVE-2026-64684","GHSA-9g45-5xwm-f3wc"]},"retained":false,"historicalAffected":[]}],"coverage":[]}