CVE-2026-33252 MCP Go SDK Allows Cross-Site Tool Execution for HTTP Servers without Authorizatrion

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site POST requests without validating the Origin header and without requiring Content-Type: application/json. In deployments without Authorization,...

CVE-2026-33252 MCP Go SDK Allows Cross-Site Tool Execution for HTTP Servers without Authorizatrion

The Go MCP SDK used Go's standard encoding/json. Prior to version 1.4.1, the Go SDK's Streamable HTTP transport accepted browser-generated cross-site POST requests without validating the Origin header and without requiring Content-Type: application/json. In deployments without Authorization,...

GHSA-WVJ2-96WP-FQ3F MCP Go SDK Vulnerable to Improper Handling of Case Sensitivity

The Go MCP SDK used Go's standard encoding/json.Unmarshal for JSON-RPC and MCP protocol message parsing. Go's standard library performs case-insensitive matching of JSON keys to struct field tags — a field tagged json:"method" would also match "Method", "METHOD", etc. Additionally, Go's standard...

CVE-2026-27896

A flaw was found in the Go MCP SDK. This issue occurs due to an improper handling of case sensitivity during JSON-RPC message parsing, specifically in the matching of JSON keys to struct field tags. This behavior violates the JSON-RPC 2.0 specification, which explicitly requires case-sensitive...

CVE-2026-27896

The Go MCP SDK used Go's standard encoding/json.Unmarshal for JSON-RPC and MCP protocol message parsing in versions prior to 1.3.1. Go's standard library performs case-insensitive matching of JSON keys to struct field tags — a field tagged json:"method" would also match "Method", "METHOD", etc...