CVE-2026-25536

Summary

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.

Affected Software

Weaknesses

• CWE-362: CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

@modelcontextprotocol/sdk: @modelcontextprotocol/sdk cross-client data leak

Additional References

• https://access.redhat.com/security/cve/CVE-2026-25536
• https://bugzilla.redhat.com/show_bug.cgi?id=2436937
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json
• https://access.redhat.com/errata/RHSA-2026:3960

References

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

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