CVE-2026-111770

{
  "etk_id": "ETK-2026-1687",
  "cve_id": "CVE-2026-111770",
  "display_id": "CVE-2026-111770",
  "ghsa_id": "GHSA-jm63-cq47-j5jp",
  "euvd_id": null,
  "status": "published",
  "anchor_state": "awaiting_cve",
  "title": "Cross-client message mix-up in @modelcontextprotocol/server",
  "summary": "@modelcontextprotocol/server versions 2.0.0 through 2.2.0 can send HTTP responses or notifications to the wrong client when multiple clients share a server instance or stateless transport. An attacker able to access such a shared endpoint may receive another client's messages when request identifiers overlap.",
  "mitigation": "Upgrade @modelcontextprotocol/server to 2.3.0 or later. Create separate server and transport instances per request or session, or use a handler factory that creates a new server for each call.",
  "vendor": "npm",
  "product": "npm:@modelcontextprotocol/server",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        ">= 2.0.0, < 2.3.0"
      ],
      "ecosystem": "npm",
      "fixed_versions": [
        "2.3.0"
      ],
      "package_name": "@modelcontextprotocol/server",
      "purl": "pkg:npm/@modelcontextprotocol/server"
    }
  ],
  "cwes": [
    362
  ],
  "cvss_score": 7.7,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "deterministic",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 28.681296133333333,
  "t0_at": null,
  "signals": {
    "trigger_signal": {
      "at": "2026-10-15T13:10:24+00:00",
      "days": -5.653087668715278,
      "is_lower_bound": true,
      "measured_at": "2026-10-21T04:50:50.796349+00:00",
      "url": "https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-jm63-cq47-j5jp"
    }
  }
}