51 matches found
CVE-2026-116684
A flaw was found in the Model Context Protocol MCP Python SDK. This vulnerability allows a remote authenticated attacker to bypass authentication and gain unauthorized access to an MCP server by presenting a valid token issued for a different service. The issue occurs because server-side...
Model Context Protocol Python SDK: Server Bearer-token Authentication Accepts Tokens Issued For A Different Resource Ser
Summary In affected versions, the SDK's server-side bearer authentication had no way to check that a token was issued for your server its audience. Where one authorization server issues tokens for several services, a valid token for another service was also accepted by your MCP server. Am I...
CVE-2026-116685
The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamablehttpclient, streamablehttpclient, sseclient, ClientSessionGroup, OAuth, and createmcphttpclient client paths enable followredirects and...
CVE-2026-116686
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, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing...
CVE-2026-116684
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 tokenverifier accepts a valid token issued for another service when the...
Model Context Protocol Python SDK: Client Fetched Server-chosen $ref URLs While Validating Tool Results Against Output S
Summary In affected versions, when a connected MCP server declared an "outputSchema" for a tool, the SDK's client validated each "calltool" result with "jsonschema"'s default resolver, which fetches any "$ref" it cannot resolve locally by opening the URL. A server could therefore put an "http://"...
Model Context Protocol Python SDK: HTTP Client Transports Followed Cross-origin Redirects Carrying Custom Headers And Bo
Summary In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client for example an "X-API-Key" credential were sent to that origin,...
GHSA-W4FH-QVV9-3V23 Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server
Summary In affected versions, the SDK's server-side bearer authentication had no way to check that a token was issued for your server its audience. Where one authorization server issues tokens for several services, a valid token for another service was also accepted by your MCP server. Am I...
Model Context Protocol Python SDK: Server bearer-token authentication accepts tokens issued for a different resource server
Summary In affected versions, the SDK's server-side bearer authentication had no way to check that a token was issued for your server its audience. Where one authorization server issues tokens for several services, a valid token for another service was also accepted by your MCP server. Am I...
Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies
Summary In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client for example an X-API-Key credential were sent to that origin, an...
GHSA-5H93-6WHR-6Q8J Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies
Summary In affected versions, the SDK's Streamable HTTP and SSE client transports followed HTTP redirects to any host. If the configured MCP endpoint answered with a redirect to a different origin: - custom headers set on the client for example an X-API-Key credential were sent to that origin, an...
GHSA-RWRF-2PQF-9J8J Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas
Summary In affected versions, when a connected MCP server declared an outputSchema for a tool, the SDK's client validated each calltool result with jsonschema's default resolver, which fetches any $ref it cannot resolve locally by opening the URL. A server could therefore put an http://, https://...
Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas
Summary In affected versions, when a connected MCP server declared an outputSchema for a tool, the SDK's client validated each calltool result with jsonschema's default resolver, which fetches any $ref it cannot resolve locally by opening the URL. A server could therefore put an http://, https://...
CVE-2026-116685
The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamablehttpclient, streamablehttpclient, sseclient, ClientSessionGroup, OAuth, and createmcphttpclient client paths enable followredirects and...
CVE-2026-116684
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 tokenverifier accepts a valid token issued for another service when the...
CVE-2026-116686
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, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing...
CVE-2026-116686
The Model Context Protocol Python SDK contains a vulnerability in versions 1.10.0 through 1.30.0 and 2.2.0 . The ClientSession, ClientSessionGroup, and Client tool calls use the default resolver in jsonschema to validate server-declared outputSchema documents. This allows a server to provide an u...
EUVD-2026-111366
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, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing...
CVE-2026-116686 Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas
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, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing...
CVE-2026-116686 Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas
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, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing...