Security: Transitive dependencies with known vulnerabilities in @modelcontextprotocol/sdk@1.29.0

Summary

@modelcontextprotocol/sdk@1.29.0 ships with transitive dependencies that have known security vulnerabilities. Downstream consumers running npm audit --audit-level=high get a non-zero exit code, breaking CI pipelines.

Affected dependencies

Dependency chain

@modelcontextprotocol/sdk@1.29.0
├── ajv@8.18.0
│   └── fast-uri@3.1.0          ← HIGH: path traversal, host confusion
├── hono@4.12.14                ← moderate: bodyLimit bypass, JSX injection, JWT validation, cache leakage
├── @hono/node-server@1.19.14
│   └── hono@4.12.14 (deduped)
└── express-rate-limit@8.4.0
    └── ip-address@10.1.0       ← moderate: XSS in Address6

Reproduction

mkdir repro && cd repro
npm init -y
npm install @modelcontextprotocol/sdk@1.29.0
npm audit --audit-level=high
# Exit code: 1

Suggested fix

All existing semver ranges in the SDK's package.json already allow the fixed versions. A lockfile regeneration or minimum version bump in package.json resolves all four:

// package.json (suggested minimum version bumps)
{
  "dependencies": {
    "ajv": "^8.18.0",              // fast-uri ^3.0.1 resolves to 3.1.2 ✓
    "hono": "^4.12.18",           // was ^4.11.4
    "express-rate-limit": "^8.5.1" // was ^8.2.1, pulls ip-address ≥10.2.0
  }
}

No breaking changes — all fixes are patch/minor semver-compatible.

Impact

Any downstream project with npm audit in CI (standard security practice) fails on --audit-level=high due to fast-uri. This blocks releases and forces consumers to add overrides as a workaround.

Workaround (for downstream consumers)

// package.json
{
  "overrides": {
    "fast-uri": ">=3.1.2",
    "hono": ">=4.12.18",
    "ip-address": ">=10.2.0",
    "express-rate-limit": ">=8.5.1"
  }
}

Environment

• @modelcontextprotocol/sdk: 1.29.0 (latest as of 2025-05-11)
• Node.js: 22.x
• npm: 10.x
• OS: Ubuntu 24.04 (CI), macOS 15 (local)

Inspect package.json and the generated lockfile, then reproduce the issue with npm install @modelcontextprotocol/sdk@1.29.0 and npm audit --audit-level=high. Update the dependency resolution or minimum ranges for the four affected packages, and verify that npm audit no longer reports the high-severity vulnerability.