Cost Calculator Builder PRO <= 4.0.3 - Unauthenticated Remote Code Execution via 'orderDetails' Parameter

The Cost Calculator Builder PRO plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 4.0.3 via the js_to_php function. This is due to insufficient sanitization of the orderDetails[*].originalValue field, which is injected verbatim into a calculator formula string passed to PHP eval() inside js_to_php(), with the regex allow-list in evaluateFormula() only filtering alphanumeric tokens and leaving non-word punctuation characters intact. This makes it possible for unauthenticated attackers to execute code on the server. The only authentication barrier is a nonce check, but the required nonce is publicly emitted on every front-end page via the wp_head hook, making it freely obtainable by unauthenticated visitors. Payloads must be non-word XOR gadgets to bypass sanitization.

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Cost Calculator Builder PRO 4.0.4 closes this, and updating the plugin is the step that ends it.

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