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CVE-2026-116684

CVE-2026-116684 · Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server

This page contains facts from public vulnerability sources. Check the original advisory before updating.

The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, server-side bearer authentication configured through AuthSettings with token_verifier accepts a valid token issued for another service when the authorization server serves multiple resources and the TokenVerifier does not independently validate the aud audience. This resource-confusion flaw lets a token holder authenticate to the wrong MCP server and exercise that token's resulting access. This issue is fixed in versions 1.30.0 and 2.2.0.

CVSS 6.8 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • python-sdk

    Versions
    • >= 1.10.0, < 1.30.0: Affected
    • >= 2.0.0, < 2.2.0: Affected

    No fix published

  • mcp PyPI

    Versions
    • 2.0.0
    • 2.0.1
    • 2.1.0
    • 2.1.1
    Affected ranges
    • ECOSYSTEM: ≥ 2.0.0, < 2.2.0

    Update to 2.2.0

  • mcp PyPI

    Versions
    • 1.10.0
    • 1.10.1
    • 1.11.0
    • 1.12.0
    • 1.12.1
    • 1.12.2
    • 1.12.3
    • 1.12.4
    • 1.13.0
    • 1.13.1
    • 1.14.0
    • 1.14.1
    • 1.15.0
    • 1.16.0
    • 1.17.0
    • 1.18.0
    • 1.19.0
    • 1.20.0
    • 1.21.0
    • 1.21.1
    • 1.21.2
    • 1.22.0
    • 1.23.0
    • 1.23.1
    • 1.23.2
    • 1.23.3
    • 1.24.0
    • 1.25.0
    • 1.26.0
    • 1.27.0
    • 1.27.1
    • 1.27.2
    • 1.28.0
    • 1.28.1
    • 1.29.0
    • 1.29.1
    Affected ranges
    • ECOSYSTEM: ≥ 1.10.0, < 1.30.0

    Update to 1.30.0

Original sources

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