CVE-2026-25536: Model Context Protocol SDK cross-client data leak

# CVE-2026-25536: Model Context Protocol SDK cross-client data leak

https://gcdradar.vercel.app/incidents/cve-2026-25536-model-context-protocol-sdk-cross-client-data · AIR-2026-0454 · closed 2026-02-04

- Lane: Patch now
- Severity: 2 (Disclosed vulnerability)
- Fix status: Fix status unknown
- First reported: 2026-02-04
- AI role: Attack on AI
- Products: @modelcontextprotocol/sdk
- CVE ids: CVE-2026-25536
- CVSS: 7.1

## Summary

A cross-client data leak vulnerability in the Model Context Protocol SDK stems from reusing server or transport instances across requests. Developers are urged to update their SDK packages.

## What to do

No action recorded; read the sources below and the vendor's advisory.

## Latest updates

- 2026-02-04: CVE-2026-25536: MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. (https://nvd.nist.gov/vuln/detail/CVE-2026-25536)
- 2026-02-04: CVE-2026-25536: @modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse (https://github.com/advisories/GHSA-345p-7cg4-v4c7)

## Sources

- 2026-02-04 GitHub Advisory Database: CVE-2026-25536: @modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse https://github.com/advisories/GHSA-345p-7cg4-v4c7
- 2026-02-04 NVD: CVE-2026-25536: MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. https://nvd.nist.gov/vuln/detail/CVE-2026-25536

Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.