CVE-2026-3576

What is known

The Planyo Online Reservation System plugin for WordPress is vulnerable to Server-Side Request Forgery leading to Local File Inclusion in all versions up to, and including, 3.0. The ulap.php file acts as an AJAX proxy and is directly accessible without WordPress bootstrapping or any authentication. The send_http_post() function validates the host of the provided URL against an allowlist that includes 'localhost', but critically fails to validate the URL scheme/protocol. This makes it possible for unauthenticated attackers to supply a file:// URL (e.g., file://localhost/etc/passwd) which bypasses the host allowlist check because parse_url() returns 'localhost' as the host. The URL is then passed to curl_init() or fopen(), both of which support the file:// protocol, allowing the attacker to read arbitrary local files on the server and have their contents returned in the HTTP response. This can lead to disclosure of sensitive files such as /etc/passwd, wp-config.php (containing database credentials and authentication keys), and other server-side files.

Business impact

Successful exploitation of CVE-2026-3576, a high vulnerability (CVSS 7.2) affecting the affected product, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether the affected product is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

• NVD
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