GHSA-9H9M-RR67-9JPG

Vulnerability from github – Published: 2026-04-08 00:06 – Updated: 2026-04-08 00:06
VLAI
Summary
coursevault-preview has a path traversal due to improper base-directory boundary validation
Details

Summary

coursevault-preview versions prior to 0.1.1 contain a path traversal vulnerability in the resolveSafe utility. The boundary check used String.prototype.startsWith(baseDir) on a normalized path, which does not enforce a directory boundary. An attacker who controls the relativePath argument to affected CoursevaultPreview methods may be able to read files outside the configured baseDir when a sibling directory exists whose name shares the same string prefix.

Details

The vulnerable code in src/utils/errors.ts:

if (!full.startsWith(base)) {   // ← insufficient
  throw new Error("Path escapes the base directory");
}

Because the check is a raw string prefix test rather than a path-boundary test, the following bypass is possible:

baseDir  = "/srv/courses"
payload  = "../courses-admin/config.json"
resolved = "/srv/courses-admin/config.json"

"/srv/courses-admin/config.json".startsWith("/srv/courses") // → true ✗

Any file whose absolute path begins with the baseDir string — including files in sibling directories that share a name prefix — passes the guard and can be accessed by the caller through affected file-access methods.

The fix replaces the check with a separator-aware comparison:

if (full !== base && !full.startsWith(base + sep)) {
  throw new Error("Path escapes the base directory");
}

Impact

An application that passes untrusted input as the relativePath argument to affected file-access methods may expose file contents outside the intended directory.

  1. Attacker control over the relativePath parameter.
  2. A sibling directory on the filesystem whose name shares a string prefix with baseDir.

There is no network exposure in the package itself; impact is limited to local file disclosure within the host process's file system permissions.

Severity
5.1 (Medium)
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "coursevault-preview"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35613"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-08T00:06:03Z",
    "nvd_published_at": "2026-04-07T17:16:35Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\n`coursevault-preview` versions prior to `0.1.1` contain a path traversal vulnerability in the `resolveSafe` utility. The boundary check used `String.prototype.startsWith(baseDir)` on a normalized path, which does not enforce a directory boundary. An attacker who controls the `relativePath` argument to affected `CoursevaultPreview` methods may be able to read files outside the configured `baseDir` when a sibling directory exists whose name shares the same string prefix.\n\n## Details\n\nThe vulnerable code in `src/utils/errors.ts`:\n\n```ts\nif (!full.startsWith(base)) {   // \u2190 insufficient\n  throw new Error(\"Path escapes the base directory\");\n}\n```\n\nBecause the check is a raw string prefix test rather than a path-boundary test, the following bypass is possible:\n\n```\nbaseDir  = \"/srv/courses\"\npayload  = \"../courses-admin/config.json\"\nresolved = \"/srv/courses-admin/config.json\"\n\n\"/srv/courses-admin/config.json\".startsWith(\"/srv/courses\") // \u2192 true \u2717\n```\n\nAny file whose absolute path begins with the `baseDir` string \u2014 including files in sibling directories that share a name prefix \u2014 passes the guard and can be accessed by the caller through affected file-access methods.\n\nThe fix replaces the check with a separator-aware comparison:\n\n```ts\nif (full !== base \u0026\u0026 !full.startsWith(base + sep)) {\n  throw new Error(\"Path escapes the base directory\");\n}\n```\n\n## Impact\n\nAn application that passes untrusted input as the `relativePath` argument to affected file-access methods may expose file contents outside the intended directory.\n\n1. Attacker control over the `relativePath` parameter.\n2. A sibling directory on the filesystem whose name shares a string prefix with `baseDir`.\n\nThere is no network exposure in the package itself; impact is limited to local file disclosure within the host process\u0027s file system permissions.",
  "id": "GHSA-9h9m-rr67-9jpg",
  "modified": "2026-04-08T00:06:03Z",
  "published": "2026-04-08T00:06:03Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/moritzmyrz/coursevault-preview/security/advisories/GHSA-9h9m-rr67-9jpg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35613"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/moritzmyrz/coursevault-preview"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "coursevault-preview has a path traversal due to improper base-directory boundary validation"
}



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