{
 "id": "CVE-2026-59950",
 "description": "The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that exposed that transport. This issue is fixed in version 1.28.1.",
 "published": "2026-07-15",
 "last_modified": "2026-10-24",
 "vuln_status": "Analyzed",
 "cna": "security-advisories@github.com",
 "cvss": {
  "version": "4.0",
  "score": 7.6,
  "severity": "HIGH",
  "vector": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
  "source": "security-advisories@github.com"
 },
 "cwe": [
  "CWE-346",
  "CWE-1385"
 ],
 "products": [
  {
   "vendor": "lfprojects",
   "product": "mcp_python_sdk",
   "versions_affected": "< 1.28.1",
   "fixed_in": "1.28.1",
   "product_id": null
  }
 ],
 "category": "protocol",
 "surface": [],
 "kev": null,
 "fix": {
  "status": "fixed",
  "version": "1.28.1",
  "url": "https://github.com/modelcontextprotocol/python-sdk/commit/777b8d06710c140e3606b0d4598e2aa48546c266"
 },
 "references": [
  {
   "url": "https://github.com/modelcontextprotocol/python-sdk/commit/777b8d06710c140e3606b0d4598e2aa48546c266",
   "source": "security-advisories@github.com",
   "tags": [
    "Patch"
   ]
  },
  {
   "url": "https://github.com/modelcontextprotocol/python-sdk/pull/2992",
   "source": "security-advisories@github.com",
   "tags": [
    "Issue Tracking",
    "Patch"
   ]
  },
  {
   "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.28.1",
   "source": "security-advisories@github.com",
   "tags": [
    "Release Notes"
   ]
  },
  {
   "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-vj7q-gjh5-988w",
   "source": "security-advisories@github.com",
   "tags": [
    "Vendor Advisory"
   ]
  }
 ],
 "related_agents": [
  "modelcontextprotocol-python-sdk",
  "modelcontextprotocol-typescript-sdk"
 ],
 "related_incidents": [],
 "match": {
  "tests": [
   "A:name",
   "B:vocabulary"
  ],
  "terms": [
   "mcp-sdk:MCP Python SDK",
   "model context protocol"
  ]
 },
 "status": "candidate",
 "note": null,
 "reviewer": null,
 "checked_on": null,
 "retrieved_on": "2026-10-26"
}