Vulnerability Report

CVE-2026-25536

Title: Cross-client response data leak in MCP TypeScript SDK

Arbitrary File Access

Proof Of Concept

No public PoC currently indexed for CVE-2026-25536.

CWE Category CWE-362

Published Date Feb 04, 2026

Modified Date Mar 18, 2026

Exploit Status Not Found

Score 7.1 CVSS v3.1

Exploit Probability (EPSS)

0.24%

Vulnerability Summary

CVE-2026-25536: 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.

Impacted Vendors

lfprojects 1

Reference Links

https://github.com/modelcontextprotocol/typescript-sdk/issues/204 https://github.com/modelcontextprotocol/typescript-sdk/issues/243 https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.1

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-25536 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

March 18, 2026 MODIFIED

Vulnerability data updated via NVD.

March 18, 2026 MODIFIED

Vulnerability data updated via NVD.

February 05, 2026 MODIFIED

Vulnerability data updated via NVD.

February 04, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected Stack

No specific products linked.