Source: image (security level: low)
Flip the security level in the header to compare the vulnerable and fixed code paths.
<?php // LOW: the file path is used as-is -> path traversal / LFI-read (open_basedir confines it to the
// webroot, so system files are blocked, but any app source can be read -> source disclosure).
$f = isset($_GET['file']) ? $_GET['file'] : 'assets/shipping.txt';
// the viewer serves store documents; it must not expose the app's ops data (the visitor log under /var/lib)
$rp = realpath($f);
$content = ($rp !== false && strpos($rp, '/var/lib/') === 0) ? false : @file_get_contents($f);