CVE-2026-67432 MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process...

CVE-2026-67431 MCP Ruby SDK: Ruby SSE Session Poisoning

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that...

CVE-2026-67430

CVE-2026-67430 affects the MCP Ruby SDK (mcp gem) prior to 0.23.0. The vulnerability is in MCP::Server::Transports::StreamableHTTPTransport, which does not expire sessions by default, allowing repeated initialize requests to retain unbounded ServerSession objects and cause memory exhaustion. The ...

CVE-2026-67430 MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not expire sessions by default, so repeated initialize requests retain unbounded ServerSession objects and can exhaust proces...

PT-2026-65899

Name of the Vulnerable Software and Affected Versions mcp versions prior to 0.23.0 Description The MCP::Server::Transports::StreamableHTTPTransport component in the mcp gem reads and parses an entire JSON-RPC POST body without enforcing a size limit. This allows an unauthenticated remote attacker...

CVE-2026-16496

The terraform-mcp-server before version 1.1.0 is vulnerable to an authorization bypass in the streamable-HTTP stateful transport mode that may allow a user who obtains another user's MCP session ID to have their tool calls executed using that user's Terraform credentials. This vulnerability,...

EUVD-2026-49940

The terraform-mcp-server before version 1.1.0 is vulnerable to an authorization bypass in the streamable-HTTP stateful transport mode that may allow a user who obtains another user's MCP session ID to have their tool calls executed using that user's Terraform credentials. This vulnerability,...

CVE-2026-16496 terraform-mcp-server vulnerable to cross-user credential inheritance if an MCP session ID is obtained by another user

The terraform-mcp-server before version 1.1.0 is vulnerable to an authorization bypass in the streamable-HTTP stateful transport mode that may allow a user who obtains another user's MCP session ID to have their tool calls executed using that user's Terraform credentials. This vulnerability,...

PYSEC-2026-3482 MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal

Summary In affected versions, the SSE and Streamable HTTP server transports routed incoming requests to an existing session based only on the session identifier, without verifying that the request was authenticated as the same principal that created the session. Anyone who learned or guessed a...

meta-ads-mcp: Server-Side Request Forgery (SSRF) in `upload_ad_image` via Unrestricted `image_url` Fetch

Server-Side Request Forgery SSRF in uploadadimage via Unrestricted imageurl Fetch Summary The uploadadimage MCP tool in meta-ads-mcp v1.0.113 passes an attacker-controlled imageurl parameter directly to an HTTP fetch helper httpx.AsyncClientfollowredirects=True.geturl without any scheme, host, or...

DNS Rebinding

Overview mcp is a The official Ruby SDK for Model Context Protocol servers and clients Affected versions of this package are vulnerable to DNS Rebinding in the handlepost method of MCP::Server::Transports::StreamableHTTPTransport in lib/mcp/server/transports/streamablehttptransport.rb, which...

PYSEC-2026-1618 MCP Python SDK has Unhandled Exception in Streamable HTTP Transport, Leading to Denial of Service

If a client deliberately triggers an exception after establishing a streamable HTTP session, this can lead to an uncaught ClosedResourceError on the server side, causing the server to crash and requiring a restart to restore service. Impact may vary depending on the deployment conditions, and...

CVE-2026-7663

IBM Langflow OSS 1.0.0 through 1.9.6 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint...

CVE-2026-7663

Langflow OSS 1.0.0–1.9.6 is affected by an improper authorization vulnerability in the Streamable MCP transport endpoint (/api/v1/mcp/project/{project_id}/streamable) that allows unauthenticated attackers to access protected MCP resources and perform MCP operations. IBM bulletin cites cross‑user ...

CVE-2026-7663 Unauthenticated Cross-User MCP Resource Access and Tool Execution via Streamable Transport Authorization Bypass

IBM Langflow OSS 1.0.0 through 1.9.6 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint...

PYSEC-2026-331 excel-mcp-server has a Path Traversal issue

Summary A path traversal vulnerability exists in excel-mcp-server versions up to and including 0.1.7. When running in SSE or Streamable-HTTP transport mode the documented way to use this server remotely, an unauthenticated attacker on the network can read, write, and overwrite arbitrary files on...

Security Bulletin: Unauthenticated Cross-User MCP Resource Access and Tool Execution via Streamable Transport Authorization Bypass

Summary An improper authorization vulnerability in Streamable MCP transport endpoint /api/v1/mcp/project/projectid/streamable allows unauthenticated attackers to bypass project ownership controls and execute Model Context Protocol MCP operations against OAuth-authenticated projects owned by other...

CVE-2026-7664

IBM Langflow OSS 1.0.0 through 1.8.4 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint...

CVE-2026-7664

IBM Langflow OSS 1.0.0 through 1.8.4 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint...

EUVD-2026-38281

IBM Langflow OSS 1.0.0 through 1.8.4 could allow unauthenticated attackers to access protected MCP project resources and execute MCP operations due to improper authorization enforcement in the Streamable MCP transport endpoint...