{"id":"CVE-2026-25536","summary":"@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse","details":"MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.","aliases":["GHSA-345p-7cg4-v4c7"],"modified":"2026-08-12T03:51:12.336985208Z","published":"2026-02-04T21:29:38.276Z","related":["CGA-r633-rfm2-6vgp"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25536.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-362"]},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json"},{"type":"ADVISORY","url":"https://access.redhat.com/errata/RHSA-2026:3960"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-25536"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25536.json"},{"type":"ADVISORY","url":"https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25536"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2436937"},{"type":"REPORT","url":"https://github.com/modelcontextprotocol/typescript-sdk/issues/204"},{"type":"REPORT","url":"https://github.com/modelcontextprotocol/typescript-sdk/issues/243"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/modelcontextprotocol/typescript-sdk","events":[{"introduced":"64653f54bd69ec2f6703f7c1e0745f84d220bea7"},{"fixed":"fe9c07b465871394c7069207c86513df9c1194a4"}],"database_specific":{"extracted_events":[{"introduced":"1.10.0"},{"fixed":"1.26.0"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:lfprojects:mcp_typescript_sdk:*:*:*:*:*:*:*:*"}}],"versions":["v1.25.2","1.25.1","1.25.0","1.24.3","1.23.0","1.24.2","1.24.1","1.24.0","1.23.0-beta.0","1.22.0","1.21.1","1.21.0","1.20.2","1.20.1","1.20.0","1.19.0","1.18.2","1.18.1","1.18.0","1.17.5","1.17.4","1.17.3","1.17.2","1.17.1","1.17.0","1.16.0","1.15.1","0.15.1","1.15.0","1.14.0","1.13.3","1.13.2","1.13.1","1.13.0","1.12.3","1.12.2","1.12.1","1.12.0","1.11.4","1.11.3","1.11.2","1.11.1","1.11.0","1.10.2","1.10.1","1.10.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-25536.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"}]}