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.
History

Thu, 05 Feb 2026 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 05 Feb 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-367
References
Metrics threat_severity

None

threat_severity

Important


Thu, 05 Feb 2026 11:45:00 +0000

Type Values Removed Values Added
First Time appeared Modelcontextprotocol
Modelcontextprotocol typescript-sdk
Vendors & Products Modelcontextprotocol
Modelcontextprotocol typescript-sdk

Wed, 04 Feb 2026 21:45:00 +0000

Type Values Removed Values Added
Description 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.
Title @modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
Weaknesses CWE-362
References
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-02-04T21:29:38.276Z

Updated: 2026-02-05T20:58:17.103Z

Reserved: 2026-02-02T19:59:47.374Z

Link: CVE-2026-25536

cve-icon Vulnrichment

Updated: 2026-02-05T20:58:11.079Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-02-04T22:15:59.663

Modified: 2026-02-05T14:57:20.563

Link: CVE-2026-25536

cve-icon Redhat

Severity : Important

Publid Date: 2026-02-04T21:29:38Z

Links: CVE-2026-25536 - Bugzilla