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: 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-2026-63118

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...

RLSA-2026:33512 Important: ruby security update

Ruby is an extensible, interpreted, object-oriented, scripting language. It has features to process text files and to perform system management tasks. Security Fixes: ruby/net-imap: ruby: Net::IMAP: IMAP Command Injection via Symbol Arguments CVE-2026-42258 net-imap: ruby: Net::IMAP: Information...

ruby security update

An update is available for ruby. This update affects Rocky Linux 9. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for each vulnerability from the CVE list Ruby is an extensible, interpreted, object-oriented, scripting language. It has...

json: Ruby JSON: Denial of service via heap buffer overflow with oversized streamed objects

A flaw was found in Ruby JSON. A remote attacker could exploit a heap buffer overflow vulnerability by providing an oversized streamed object containing a specially crafted string. This could lead to a reliable process crash, resulting in a denial of service DoS for the affected system...

Low: Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

An update for Red Hat Hardened Images RPMs is now available. This update includes the following RPMs: ruby4.0: ruby4.0-4.0.6-37.1.hum1 aarch64, x8664 ruby4.0-bundled-gems-4.0.6-37.1.hum1 aarch64, x8664 ruby4.0-default-gems-4.0.6-37.1.hum1 noarch ruby4.0-devel-4.0.6-37.1.hum1 aarch64, x8664...

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-2026-63118: 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...

Linux Distros Unpatched Vulnerability : CVE-2026-54619

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - sqlite3 provides Ruby bindings for the SQLite3 embedded database. In version 2.9.4 and earlier, redefining a SQLite function with a different arity frees the...

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...

Linux Distros Unpatched Vulnerability : CVE-2026-54603

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - OAuth2 is a Ruby wrapper for the OAuth 2.0 and 2.1 authorization frameworks, including OpenID Connect OIDC. From 0.4.0 to 2.0.21, a protocol-relative redirect...

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...

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...

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-2026-67432: 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...

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...

RockyLinux 9 : ruby (RLSA-2026:33512)

The remote RockyLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RLSA-2026:33512 advisory. ruby/net-imap: ruby: Net::IMAP: IMAP Command Injection via Symbol Arguments CVE-2026-42258 net-imap: ruby: Net::IMAP: Information disclosure via...

Linux Distros Unpatched Vulnerability : CVE-2026-54620

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - sqlite3 provides Ruby bindings for the SQLite3 embedded database. From 2.1.0 to 2.9.4, the callbacks used for SQLite aggregate functions can be freed while stil...