CVE-2026-25536
@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
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.
INFO
Published Date :
Feb. 4, 2026, 10:15 p.m.
Last Modified :
March 18, 2026, 2:22 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the MCP TypeScript SDK to version 1.26.0.
- Avoid reusing transport instances across client connections.
Public PoC/Exploit Available at Github
CVE-2026-25536 has a 23 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-25536.
| URL | Resource |
|---|---|
| https://github.com/modelcontextprotocol/typescript-sdk/issues/204 | Issue Tracking Vendor Advisory |
| https://github.com/modelcontextprotocol/typescript-sdk/issues/243 | Issue Tracking Vendor Advisory |
| https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7 | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-25536 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-25536
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Scan, Score, Install MCP Servers with confidence. The missing toolkit for the MCP ecosystem.
ai-safety audit cli-tool mcp mcp-server model-context-protocol python scanner security vulnerability-scanner cli devtools llm-security
Python
None
Shell TypeScript JavaScript Python
Production security middleware for MCP servers - DNS rebinding protection, CORS guard, tool filtering
Python TypeScript
None
Shell TypeScript JavaScript Python
堪称文档工程杰作。本指南覆盖 Claude Code 从入门到精通的完整路径，附生产级模板、智能体工作流实战教程、海量学习资源（包括测验 + 速查表）。至于它到底是不是 Claude Code 的"终极指南"——你说了算 :)
Shell TypeScript JavaScript Python HTML
None
Shell TypeScript JavaScript Python
None
Shell TypeScript JavaScript Python
The Project shares all information on MCP related CVE's published
mcp mcp-security mcp-cve
None
Shell TypeScript JavaScript Python
macOS vulnerability check script - detects 23 recent supply chain attacks and CVEs (Jan-Apr 2026)
Shell
None
TypeScript JavaScript Shell Python
None
TypeScript JavaScript Shell Python
A practitioner-focused reference for AI/ML security — attacks, tools, research, and defenses. Covers offensive AI, securing AI systems, AI-assisted security operations, and governance.
🤖 Curated AI OSINT resources — Google dorks, Shodan queries, GitHub dorks, and techniques to discover exposed LLM endpoints, leaked AI API keys, misconfigured vector databases, and unprotected AI agents
ai-osint ai-security api-keys artificial-intelligence bug-bounty cybersecurity google-dorks hacking llm-security machine-learning mcp-security ollama osint owasp pentesting prompt-injection reconnaissance red-team shodan vector-database
None
TypeScript JavaScript Shell Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-25536 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-25536 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 18, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:lfprojects:mcp_typescript_sdk:*:*:*:*:*:*:*:* versions from (including) 1.10.0 up to (excluding) 1.26.0 Added Reference Type GitHub, Inc.: https://github.com/modelcontextprotocol/typescript-sdk/issues/204 Types: Issue Tracking, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/modelcontextprotocol/typescript-sdk/issues/243 Types: Issue Tracking, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7 Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
Feb. 04, 2026
Action Type Old Value New Value 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-362 Added Reference https://github.com/modelcontextprotocol/typescript-sdk/issues/204 Added Reference https://github.com/modelcontextprotocol/typescript-sdk/issues/243 Added Reference https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7