# mcp (PyPI) vulnerabilities

10 known vulnerabilities (6 high, 4 medium), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: not known (cve.now hasn't read this package's releases)
- Newest unaffected release: not known without release data
- Weekly downloads: 71.1M
- Dependents: 26.5K
- Registry: https://pypi.org/project/mcp/

## Advisories (10)

### [CVE-2026-116686](https://cve.now/CVE-2026-116686): Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas

- Severity: Medium 6.5
- Published: Oct 27, 2026
- Affected: from 2.0.0, fixed in 2.2.0; from 1.10.0, fixed in 1.30.0.

### [CVE-2026-116685](https://cve.now/CVE-2026-116685): Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies

- Severity: Medium 5.9
- Published: Oct 27, 2026
- Affected: from 2.0.0, fixed in 2.2.0; from 1.8.0, fixed in 1.30.0.

### [CVE-2026-116684](https://cve.now/CVE-2026-116684): Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server

- Severity: Medium 6.8
- Published: Oct 27, 2026
- Affected: from 2.0.0, fixed in 2.2.0; from 1.10.0, fixed in 1.30.0.

### [CVE-2026-59951](https://cve.now/CVE-2026-59951): MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion

- Severity: Medium 6.9
- Published: Oct 14, 2026
- Affected: from 1.8.0, fixed in 1.30.0; from 2.0.0, fixed in 2.2.0.

### [CVE-2026-59950](https://cve.now/CVE-2026-59950): MCP Python SDK: WebSocket server transport does not support Host/Origin validation

- Severity: High 7.6
- Published: Jul 15, 2026
- Affected: fixed in 1.28.1.

### [CVE-2026-52870](https://cve.now/CVE-2026-52870): MCP Python SDK: Experimental task handlers allow any client to access and cancel other clients' tasks

- Severity: High 7.6
- Published: Jul 15, 2026
- Affected: from 1.23.0, fixed in 1.27.2.

### [CVE-2026-52869](https://cve.now/CVE-2026-52869): MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal

- Severity: High 7.1
- Published: Jul 15, 2026
- Affected: fixed in 1.27.2.

### [CVE-2025-66416](https://cve.now/CVE-2025-66416): DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost

- Severity: High 7.6
- Published: Dec 2, 2025
- Affected: fixed in 1.23.0.

### [CVE-2025-53366](https://cve.now/CVE-2025-53366): MCP SDK Vulnerable to FastMCP Server Validation Error, Leading to Denial of Service

- Severity: High 8.7
- Published: Jul 4, 2025
- Affected: fixed in 1.9.4.

### [CVE-2025-53365](https://cve.now/CVE-2025-53365): MCP Python SDK has Unhandled Exception in Streamable HTTP Transport ,Leading to Denial of Service

- Severity: High 8.7
- Published: Jul 4, 2025
- Affected: fixed in 1.10.0.

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