CVE-2026-63118 MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection

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 validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a...

CVE-2026-63118

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 validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a...

CVE-2026-63118 MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection

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 validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a...

CVE-2026-63118

The MCP Ruby SDK (mcp gem) contains a DNS rebind vulnerability in MCP::Server::Transports::StreamableHTTPTransport where HTTP Host/Origin are not validated. This allows a malicious page to bind a victim’s locally running MCP server to a loopback/ LAN address and post JSON‑RPC requests to exposed ...

CVE-2026-67432: Allocation of Resources Without Limits or Throttling

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...

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-2026-63119: Uncontrolled Resource Consumption

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IOgets without a byte limit, allowing a peer that sends data without a newline to exhaust process memory. This...

CVE-2026-67431: Improper Access Control

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: Missing Release of Memory after Effective Lifetime

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...

CVE-2026-63118: Origin Validation Error

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 validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a...

PT-2026-65888

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 fails to validate the HTTP Host or Origin request headers. This allows a malicious browser page to utilize DNS rebinding—a...

PT-2026-65897

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 does not expire sessions by default. Consequently, repeated initialize requests lead to the retention of unbounded...

Allocation of Resources Without Limits or Throttling

Overview mcp is a The official Ruby SDK for Model Context Protocol servers and clients Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the stdio transports lib/mcp/server/transports/stdiotransport.rb and lib/mcp/client/stdio.rb, which ca...

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...

Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport

Summary An unauthenticated remote attacker can force any MCP Ruby SDK server using MCP::Server::Transports::StreamableHTTPTransport to allocate gigabytes of memory by sending a single oversized JSON-RPC POST. The transport reads the entire HTTP body into a Ruby String and parses it with...

CVE-2026-40070

BSV Ruby SDK is the Ruby SDK for the BSV blockchain. From 0.3.1 to before 0.8.2, BSV::Wallet::WalletClientacquirecertificate persists certificate records to storage without verifying the certifier's signature over the certificate contents. In acquisitionprotocol: 'direct', the caller supplies all...

EUVD-2026-20994

bsv-sdk ARC broadcaster treats INVALID/MALFORMED/ORPHAN responses as successful broadcasts...

EUVD-2026-20996

bsv-sdk and bsv-wallet persist unverified certifier signatures in acquirecertificate direct and issuance paths...

Improper Check for Unusual or Exceptional Conditions

Overview bsv-sdk is an A Ruby library for interacting with the BSV Blockchain — keys, scripts, transactions, and more. Affected versions of this package are vulnerable to Improper Check for Unusual or Exceptional Conditions due to improper handling of ARC broadcaster responses i. An attacker can...

CVE-2026-40069

BSV Ruby SDK is the Ruby SDK for the BSV blockchain. From 0.1.0 to before 0.8.2, BSV::Network::ARC's failure detection only recognises REJECTED and DOUBLESPENDATTEMPTED. ARC responses with txStatus values of INVALID, MALFORMED, MINEDINSTALEBLOCK, or any ORPHAN-containing extraInfo / txStatus are...