Vulnerabilities in pkg:npm/@gitlawb/openclaude

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-c73c-x77g-854r",
  "modified" : "2026-06-09T10:59:32Z",
  "published" : "2026-05-12T15:34:30Z",
  "aliases" : [ "CVE-2026-42073" ],
  "summary" : "OpenClaude MCP OAuth Callback: State Check Bypass via error Param Leads to DoS",
  "details" : "# OAuth State Validation Bypass via `error` Parameter Causes Local Server DoS in MCP Auth Callback\n---\n\n## Description\n\nThe OpenClaude MCP authentication flow starts a temporary local HTTP server to handle OAuth callbacks. To prevent CSRF attacks, the server validates a `state` parameter against an internally stored value. However, due to a logic flaw in the order of conditionals, an attacker can completely bypass this check and force the server to shut down — without knowing the `state` value at all.\n\nThe vulnerable code looks like this:\n\n```typescript\nif (!error && state !== oauthState) {\n    rejectOnce(new Error('OAuth state mismatch - possible CSRF attack'))\n    return\n}\n\nif (error) {\n    cleanup()\n    rejectOnce(new Error(errorMessage))\n    return\n}\n```\n\nWhen a request arrives with an `error` query parameter (e.g., `?error=anything`), the first condition becomes `false` because `!error` evaluates to `false`. This means the CSRF check is **never reached**. Execution falls through to the second block, where `cleanup()` is called — shutting down the local server and terminating the user's active authentication session.\n\nThe attacker does not need to know the `state` value. Any request containing an `error` parameter is enough to trigger the shutdown.\n\n---\n\n## Impact\n\n- The user's OAuth flow is silently terminated mid-session\n- The local callback server is shut down (Denial of Service)\n- Can be triggered remotely via a malicious web page using a cross-origin request (CSRF)\n- No authentication or prior knowledge of the `state` value is required\n\n---\n\n## Steps to Reproduce\n\nSave the following as `poc.js` and run with Node.js:\n\n```javascript\nimport { createServer } from 'http';\nimport { parse } from 'url';\n\nconst expectedState = \"secure_state_abc123\";\n\nconst server = createServer((req, res) => {\n    const parsedUrl = parse(req.url || '', true);\n    const { pathname, query } = parsedUrl;\n    const { state, error } = query;\n\n    if (pathname === '/callback') {\n\n        // Vulnerable: error param causes state check to be skipped entirely\n        if (!error && state !== expectedState) {\n            res.writeHead(400);\n            res.end('State mismatch');\n            console.log('[-] CSRF attempt blocked.');\n            return;\n        }\n\n        if (error) {\n            res.writeHead(200);\n            res.end(`Error: ${error}`);\n            console.log(`[!] Server shutting down. Triggered by: ${error}`);\n            server.close();\n            return;\n        }\n    }\n});\n\nserver.listen(12345, '127.0.0.1', () => {\n    console.log('Listening on http://127.0.0.1:12345');\n});\n```\n\n**Terminal 1 — start the server:**\n```bash\nnode poc.js\n```\n\n**Terminal 2 — trigger the bypass:**\n```bash\ncurl \"http://127.0.0.1:12345/callback?error=triggered\"\n```\n\n**Expected result:** Server shuts down immediately. The `state` value was never checked.\n\n---\n\n## Root Cause\n\nThe CSRF protection is conditioned on `!error`, meaning it is silently disabled whenever an `error` parameter is present. The two checks need to be decoupled — state validation must happen first, independently of any other parameters.\n\n---\n\n## Fix\n\nMove the `state` check before the `error` check, and remove the dependency on `!error`:\n\n```typescript\n// Fixed\nif (state !== oauthState) {\n    cleanup()\n    rejectOnce(new Error('OAuth state mismatch - possible CSRF attack'))\n    return\n}\n\nif (error) {\n    cleanup()\n    rejectOnce(new Error(errorMessage))\n    return\n}\n```\n\nWith this change, any request — whether it contains an `error` parameter or not — must first pass the state validation before any further processing occurs.\n\n---\n\nCredit: Xanlar Agamalizade",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@gitlawb/openclaude"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.5.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/Gitlawb/openclaude/security/advisories/GHSA-c73c-x77g-854r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42073"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Gitlawb/openclaude/commit/739b8d1f40fde0e401a5cbd2b9a55d88bd5124ad"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Gitlawb/openclaude"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Gitlawb/openclaude/releases/tag/v0.5.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-352", "CWE-400" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-12T15:34:30Z",
    "nvd_published_at" : "2026-06-02T17:16:31Z"
  }
}