TC-2026-0053 · NPM · MCP

[email protected]

Malicious npm MCP bridge package that modifies ~/.claude/settings.json and ~/.cursor/mcp.json during postinstall to disable hooks and register a persistent background listener.

Primary advisory (Socket Security) Back to all 66 records

Signed ledger verdict

TC-2026-0053
Known bad (exit 2) npm:[email protected]

IOC & scope: npm:[email protected]. Verified by human review and signed into the CC-BY 4.0 OSV v1.6.0 feed.

Credited finder
Socket Security ↗
Recorded timestamp
2026-04-14
Canonical SHA-256
34812f7bfc5cf646…
Local hook action
Block (exit 2)
Run live in Counter Workbench

Signed in /feed.json (.sig).

01 8-Vector Capability X-Ray (ABOM) & OWASP Agentic Crosswalk

Deterministic capability profile and taxonomy mapping.

Every artifact in the threat.cafe ledger is profiled across eight execution vectors and mapped to the OWASP Top 10 for Agentic Applications (ASI01-ASI10) and Agentic Skills & Tools (AST01-AST10).

8-Vector Capability X-Ray (ABOM)

  1. 1. Filesystem
    Sensitive paths touched: ~/.claude/settings.json, ~/.cursor/mcp.json
  2. 2. Environment
    Variables harvested: None observed
  3. 3. Network
    Outbound egress domains: None observed
  4. 4. Subprocess
    Process execution primitives: node scripts/patch-ide-config.js
  5. 5. Lifecycle
    Install / startup hooks: postinstall
  6. 6. OAuth / MCP
    Declared scopes: None observed
  7. 7. Obfuscation
    Encoding / steganography: None observed
  8. 8. Provenance
    Attestation status: unverified_npm_publisher

Governance & detector mapping

  1. OWASP Agentic ASI (2026): ASI04 (Agentic Supply Chain Vulnerabilities), ASI05 (Unexpected Code Execution (RCE))
  2. OWASP Agentic AST (2026): AST01 (Malicious MCP Servers), AST05 (Sandbox Escape & Local Execution)
  3. Deterministic rules matched: RULE_04_INSTALL_LIFECYCLE_HOOK, CONFIG_04_CLAUDE_HOOK_TAMPER, RUNTIME_02_CONFIG_WRITE_FIREWALL

Version scoping & related records

  • No other versions of this package are currently listed on the board. Unlisted versions evaluate to unknown under local policy.yml.

Local CLI verification

$ threat-cafe-hook check "npm:[email protected]"
[threat.cafe] known_bad: npm:[email protected] (TC-2026-0053)
  Reason: Malicious npm MCP bridge package that modifies ~/.claude/settings.json and ~/.cursor/mcp.j
  Source: https://socket.dev/blog (credited to Socket Security)

OSV v1.6.0 machine-readable record

Included in /feed.json under CC-BY 4.0 license and verified by /feed.json.sig.

{
  "schema_version": "1.6.0",
  "id": "TC-2026-0053",
  "modified": "2026-04-14T15:45:00Z",
  "published": "2026-04-14T15:45:00Z",
  "summary": "Malicious npm MCP bridge package that modifies ~/.claude/settings.json and ~/.cursor/mcp.json during postinstall to disable hooks and register a persistent background listener.",
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "cursor-mcp-bridge"
      },
      "versions": [
        "0.2.4"
      ]
    }
  ],
  "credits": [
    {
      "name": "Socket Security",
      "type": "FINDER"
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://socket.dev/blog"
    },
    {
      "type": "WEB",
      "url": "https://threat.cafe/incidents/tc-2026-0053/"
    }
  ],
  "database_specific": {
    "target": "npm:[email protected]",
    "kind": "mcp",
    "verdict": "known_bad",
    "ioc": "npm:[email protected]",
    "artifact_sha256": "34812f7bfc5cf6463cfa6bd897f9cb82a11eaacf19d5585f7d6e0af09edf8d7b",
    "owasp_asi": [
      "ASI04",
      "ASI05"
    ],
    "owasp_ast": [
      "AST01",
      "AST05"
    ],
    "rules_matched": [
      "RULE_04_INSTALL_LIFECYCLE_HOOK",
      "CONFIG_04_CLAUDE_HOOK_TAMPER",
      "RUNTIME_02_CONFIG_WRITE_FIREWALL"
    ],
    "abom": {
      "fs_sensitive": [
        "~/.claude/settings.json",
        "~/.cursor/mcp.json"
      ],
      "env_harvest": [],
      "net_egress": [],
      "proc_exec": [
        "node scripts/patch-ide-config.js"
      ],
      "install_hooks": [
        "postinstall"
      ],
      "oauth_scopes": [],
      "obfuscation": [],
      "provenance": "unverified_npm_publisher"
    },
    "license": "CC-BY-4.0",
    "record_digest": "sha256:196a1f5565692dfa55839b70f94433a45ebc4c8449cee5ec4e5c9f5c387944f6",
    "release_signature_url": "https://threat.cafe/feed.json.sig"
  }
}

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