CVE-2026-3576: Input Validation Flaw (CVSS 7.2)

Description

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.

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CVSS v3.1 Score

7.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0036

Probability of exploitation

0.28%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Other References

Frequently Asked Questions

What is CVE-2026-3576? +

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. It has a CVSS v3.1 base score of 7.2 (HIGH).

How severe is CVE-2026-3576? +

CVE-2026-3576 has a CVSS v3.1 score of 7.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0036, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-3576? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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