CVE-2026-25536
@modelcontextprotocol/sdk has cross-client data leak via shared server/transport instance reuse
- State
- Published
- Severity
- 7.1 High
- Published
- Feb 4, 2026
- Updated
- Jul 15, 2026
- Reserved
- Feb 2, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.1 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N | GitHub_M |
| 3.1 | 7.1 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
typescript-sdkmodelcontextprotocol |
|
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
- https://access.redhat.com/security/cve/CVE-2026-25536vdb-entry
- RHBZ#2436937issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json
- https://access.redhat.com/errata/RHSA-2026:3960vendor-advisory
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