Vulnerabilities in pkg:npm/obsidian-local-rest-api

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-62gx-5q78-wrvx",
  "modified" : "2026-07-15T21:56:45Z",
  "published" : "2026-07-15T21:56:45Z",
  "aliases" : [ ],
  "summary" : "obsidian-local-rest-api: Authenticated path traversal via URL-encoded %2F in /vault/{path} — arbitrary host file read/write/delete",
  "details" : "### Summary\nThe Local REST API's `/vault/{path}` endpoints (GET/PUT/PATCH/POST/DELETE) percent-decode the request path *inside the handler — after* Express has already routed and normalized it, then hand it to the Obsidian vault adapter with no confinement check. A literal `../` is resolved/rejected at the routing layer (→ 404), but `%2F` is not a separator there, so `..%2F..%2F` survives routing and is only turned into a real `/` by the handler's `decodeURIComponent`, reconstituting a `../` traversal that walks out of the vault. An **authenticated** client can read, write, or delete **arbitrary files on the host** with the Obsidian process's privileges.\n\n### Details\n**Framework:** Express (`import express from \"express\"`; routes registered via `this.api.route(\"/vault/*\")…`).\n\n**The vulnerable line** — in `src/requestHandler.ts`, every vault handler (`vaultGet`, `vaultPut`, `vaultPatch`, `vaultPost`, `vaultDelete`) derives the path like this:\n  ```ts\n  const rawPath = decodeURIComponent(\n    req.path.slice(req.path.indexOf(\"/\", 1) + 1),\n  );\n  ```\nThe path is `decodeURIComponent`'d **after** Express routing. A literal `../` is collapsed/rejected at the routing layer, but `%2F` isn't a separator there — so `..%2F..%2F` reaches the handler intact and this `decodeURIComponent` turns it into a real `../../`. **The string routing saw (`…%2F…`) is not the string the handler uses (`…/…`)**, and `%2e%2e` behaves the same way.\n\n**No confinement on the decoded path.** The handlers pass `rawPath` straight to the vault adapter — e.g. `this.app.vault.adapter.readBinary(filePath)` / `this.app.vault.getAbstractFileByPath(filePath)` — with no `path.resolve` + vault-root prefix check, so the reconstituted `../../` escapes.\n\n**The fix already exists in your code — for MOVE only.** `vaultMove` confines correctly:\n  ```ts\n  const syntheticRoot = \"/vault\";\n  const resolved = posix.resolve(syntheticRoot, normalized);\n  if (resolved !== syntheticRoot && !resolved.startsWith(syntheticRoot + \"/\")) {\n    this.returnCannedResponse(res, { errorCode: ErrorCode.PathTraversalNotAllowed });\n    return;\n  }\n  ```\nGET/PUT/PATCH/POST/DELETE lack this guard. **Apply the same `posix.resolve(syntheticRoot, …)` + `startsWith` check to the decoded path in every vault handler**, and reject any segment that decodes to `..`.\n\n### PoC\nPrereq: a running Obsidian with the Local REST API plugin enabled and its configured API key (`$API_KEY`). Targets below are Unix; adjust per OS (e.g. `..%2F..%2FWindows%2Fwin.ini` on Windows).\n\n  ```bash\n  # READ outside the vault (returns 200 + the target file's real bytes):\n  curl --path-as-is -k -H \"Authorization: Bearer $API_KEY\" \\\n    \"https://127.0.0.1:27124/vault/..%2F..%2F..%2F..%2Fetc%2Fpasswd\"\n\n  # WRITE outside the vault (creates a file on disk outside the vault root):\n  curl --path-as-is -k -X PUT -H \"Authorization: Bearer $API_KEY\" --data \"pwned\" \\\n    \"https://127.0.0.1:27124/vault/..%2F..%2F..%2Ftmp%2Fcanary.txt\"\n  ```\n\n`--path-as-is` stops curl from collapsing `..` client-side. A plain `../` (unencoded) request returns 404 — only the `%2F`/`%2e%2e` encoded form bypasses, confirming the decode-after-routing gap.\n\n### Impact\nAuthenticated arbitrary file **read / write / delete** outside the Obsidian vault, with the OS privileges of the Obsidian process — typically the user's home directory (SSH keys, browser profiles, dotfiles, credentials). Amplified in MCP/LLM-agent deployments: this API is widely used as an MCP server, so a prompt-injection in vault content (or a malicious MCP client) can make an agent emit a `%2F` path — turning \"the agent can edit my notes\" into \"the agent can read/write any file on the host,\" with no user intent to grant filesystem access beyond the vault.\n\nThis vulnerability was reported by Caleb Brisbin through responsible disclosure.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "obsidian-local-rest-api"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "< 4.1.3"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/coddingtonbear/obsidian-local-rest-api/security/advisories/GHSA-62gx-5q78-wrvx"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/coddingtonbear/obsidian-local-rest-api"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/coddingtonbear/obsidian-local-rest-api/releases/tag/4.1.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-15T21:56:45Z",
    "nvd_published_at" : null
  }
}