CVE-2026-59951

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...

rmcp: RMCP: Denial of Service via unauthenticated session table leak

A flaw was found in rmcp, a Rust SDK for the Model Context Protocol. An unauthenticated remote attacker can send specially crafted JSON-RPC POST requests to the stateful Streamable HTTP server. These requests cause the server to create and permanently retain session and channel state without prop...

rmcp: RMCP: Denial of Service via unauthenticated session table leak

A flaw was found in rmcp, a Rust SDK for the Model Context Protocol. An unauthenticated remote attacker can send specially crafted JSON-RPC POST requests to the stateful Streamable HTTP server. These requests cause the server to create and permanently retain session and channel state without prop...

RMCP: Unauthenticated permanent session-table leak in rmcp Streamable HTTP server transport leads to remote denial-of-service

Summary An unauthenticated remote attacker can leak one entry per HTTP request out of the in-memory session table of LocalSessionManager by sending a well-formed JSON-RPC POST that is not an InitializeRequest. The Streamable HTTP server's handlepost allocates the session before it validates the...

CVE-2026-63128

A flaw was found in rmcp, a Rust SDK for the Model Context Protocol. An unauthenticated remote attacker can send specially crafted JSON-RPC POST requests to the stateful Streamable HTTP server. These requests cause the server to create and permanently retain session and channel state without prop...

CVE-2026-63128 RMCP: Unauthenticated permanent session-table leak in rmcp Streamable HTTP server transport leads to remote denial-of-service

RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.0.0, the rmcp crate's stateful Streamable HTTP server in crates/rmcp/src/transport/streamablehttpserver/tower.rs allows an unauthenticated client to send a well-formed JSON-RPC POST that is not an initialization request, or a...

CVE-2026-63128 RMCP: Unauthenticated permanent session-table leak in rmcp Streamable HTTP server transport leads to remote denial-of-service

RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.0.0, the rmcp crate's stateful Streamable HTTP server in crates/rmcp/src/transport/streamablehttpserver/tower.rs allows an unauthenticated client to send a well-formed JSON-RPC POST that is not an initialization request, or a...

CVE-2026-63128

RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.0.0, the rmcp crate's stateful Streamable HTTP server in crates/rmcp/src/transport/streamablehttpserver/tower.rs allows an unauthenticated client to send a well-formed JSON-RPC POST that is not an initialization request, or a...

CVE-2026-63128

RMCP , the official Rust SDK for the Model Context Protocol, has an unauthenticated denial-of-service vulnerability in its stateful Streamable HTTP server (crates/rmcp/src/transport/streamable_http_server/tower.rs). Prior to version 2.0.0 , StreamableHttpService::handle_post calls LocalSessionMan...

PT-2026-93789

Name of the Vulnerable Software and Affected Versions rmcp versions prior to 2.0.0 Description The stateful Streamable HTTP server in the rmcp crate contains a memory leak that can lead to a Denial of Service. An unauthenticated remote attacker can exploit this by sending a well-formed JSON-RPC...

Denial Of Service (DoS)

Spring AI is vulnerable to Denial of Service DoS. The vulnerability is due to the MCP Streamable HTTP server transport retaining an unbounded number of unauthenticated sessions, which allows a remote attacker to exhaust server memory over time and ultimately cause a denial of service affecting...

CVE-2026-59279

The MCP Streamable HTTP server transport WebFlux and WebMvc variants does not place any limit on the number of sessions it retains, and by default does not require clients to be authenticated. As a result, a remote attacker can cause the server to accumulate an unbounded number of sessions over...

CVE-2026-59279: Allocation of Resources Without Limits or Throttling

The MCP Streamable HTTP server transport WebFlux and WebMvc variants does not place any limit on the number of sessions it retains, and by default does not require clients to be authenticated. As a result, a remote attacker can cause the server to accumulate an unbounded number of sessions over...

CVE-2026-42559

RMCP is an official Rust SDK for the Model Context Protocol. Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport crates/rmcp/src/transport/streamablehttpserver/ did not validate the incoming Host header. This allowed a malicious public website, via a DNS rebinding attack, to...

CVE-2026-42559: Origin Validation Error

RMCP is an official Rust SDK for the Model Context Protocol. Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport crates/rmcp/src/transport/streamablehttpserver/ did not validate the incoming Host header. This allowed a malicious public website, via a DNS rebinding attack, to...

PT-2026-53649

Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport did not validate the incoming Host header. This allowed a malicious public website, via a DNS rebinding attack, to send requests to an MCP server running on the victim's loopback or private-network interface. An attacker wh...