MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion

Summary In affected versions, a Streamable HTTP server in stateful mode the default never reclaimed session state: - sessions did not expire; - a client DELETE ended the session but left its entry registered; - a session whose first request was refused stayed registered with a running task. Each...

CVE-2026-59951 MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol MCP. From 1.8.0 until 1.30.0 and 2.2.0, stateful Streamable HTTP servers, including FastMCP, MCPServer, Server.streamablehttpapp, and StreamableHTTPSessionManager, retain session entries without an id...

CVE-2026-59951

The MCP Python SDK (PyPI: mcp) versions 1.8.0 through 1.30.0 and 2.2.0 are vulnerable to unbounded session accumulation within the StreamableHTTP transport . Specifically, stateful servers—including FastMCP , MCPServer , Server.streamable_http_app() , and StreamableHTTPSessionManager —fail to exp...

CVE-2026-59951 MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion

The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol MCP. From 1.8.0 until 1.30.0 and 2.2.0, stateful Streamable HTTP servers, including FastMCP, MCPServer, Server.streamablehttpapp, and StreamableHTTPSessionManager, retain session entries without an id...

SUSE CVE-2026-81092

mcp-go accepted requests on its HTTP transports without checking the Host header. StreamableHTTPServer.ServeHTTP in server/streamablehttp.go and SSEServer.ServeHTTP in server/sse.go served any request arriving over a loopback connection regardless of the host it named, and the SSE transport's...

github.com/mark3labs/mcp-go: mcp-go: DNS Rebinding vulnerability due to missing Host header validation

A flaw was found in mcp-go. This component failed to validate the Host header in HTTP requests, specifically within its StreamableHTTPServer and SSEServer transports. A remote attacker could exploit this by using a crafted web page to perform a DNS rebinding attack. This allows the attacker to...

github.com/mark3labs/mcp-go: mcp-go: DNS Rebinding vulnerability due to missing Host header validation

A flaw was found in mcp-go. This component failed to validate the Host header in HTTP requests, specifically within its StreamableHTTPServer and SSEServer transports. A remote attacker could exploit this by using a crafted web page to perform a DNS rebinding attack. This allows the attacker to...

CVE-2026-35577: Origin Validation Error

Apollo MCP Server is a Model Context Protocol server that exposes GraphQL operations as MCP tools. Prior to version 1.7.0, the Apollo MCP Server did not validate the Host header on incoming HTTP requests when using StreamableHTTP transport. In configurations where an HTTP-based MCP server is run ...

CVE-2025-54382

Cherry Studio is a desktop client that supports for multiple LLM providers. In version 1.5.1, a remote code execution RCE vulnerability exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The issue arises from the server’s implicit trust in the oauth auth redirecti...

CVE-2025-54382

Cherry Studio is a desktop client that supports for multiple LLM providers. In version 1.5.1, a remote code execution RCE vulnerability exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The issue arises from the server’s implicit trust in the oauth auth redirecti...

CVE-2025-54382 Cherry Studio RCE Vulnerability Disclosure

Cherry Studio is a desktop client that supports for multiple LLM providers. In version 1.5.1, a remote code execution RCE vulnerability exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The issue arises from the server’s implicit trust in the oauth auth redirecti...

CVE-2025-54382

Cherry Studio is a desktop client that supports for multiple LLM providers. In version 1.5.1, a remote code execution RCE vulnerability exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The issue arises from the server’s implicit trust in the oauth auth redirecti...

CVE-2025-54382: Improper Neutralization of Special Elements used in an OS Command

Cherry Studio is a desktop client that supports for multiple LLM providers. In version 1.5.1, a remote code execution RCE vulnerability exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The issue arises from the server’s implicit trust in the oauth auth redirecti...

PT-2025-32990

Name of the Vulnerable Software and Affected Versions Cherry Studio versions prior to 1.5.2 Description Cherry Studio is a desktop client that supports multiple LLM providers. A remote code execution RCE issue exists in the Cherry Studio platform when connecting to streamableHttp MCP servers. The...