Cost Calculator Builder <= 4.0.11 - Unauthenticated Sensitive Information Exposure of Payment Gateway Secret Keys
The Cost Calculator Builder plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 4.0.11 via the (template body). This makes it possible for unauthenticated attackers to extract the plaintext Stripe secret key, Razorpay secret key, and PayPal client_secret embedded in the page source of any page containing a calculator, enabling full control of the merchant's payment gateway accounts. This exposure only occurs when the 'use in all calculators' option is enabled for one or more payment gateways in the plugin's global settings.
Quick answer
Cost Calculator Builder should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- *-4.0.11
Fixed versions
- 4.0.12
How to fix it
Cost Calculator Builder is affected by CVE-2026-10865, a information disclosure issue in versions up to 4.0.11. Wordfence lists the official remediation as updating to version 4.0.12, or a newer patched version. Prioritize internet-facing WordPress sites, sites with public registration, customer portals, support, booking, import/export, page-builder, and admin workflows where the vulnerable feature is enabled. If immediate patching is not possible, disable the affected plugin or feature, restrict access, and monitor for exploitation until the update is installed.
- Inventory every WordPress site that has Cost Calculator Builder installed, including production, staging, multisite, client, WooCommerce, support, booking, and content-management environments.
- Confirm the installed Cost Calculator Builder version and compare it with the affected range from the Wordfence advisory.
- Update Cost Calculator Builder to version 4.0.12, or to a newer vendor-supported patched version from the official WordPress update channel.
- If the update cannot be applied immediately, disable Cost Calculator Builder or the affected feature and restrict access with roles, authentication, WAF rules, or temporary route blocking.
- Review exposed records, exports, form entries, tickets, user profile data, orders, bookings, logs, and plugin data that may have been accessed by unauthorized users.
- Rotate administrator sessions, API keys, webhook secrets, payment or integration tokens, and affected credentials if logs or content review suggest compromise.
- Clear WordPress, object, CDN, page-builder, security plugin, WooCommerce, booking/support plugin, and browser caches after patching so vulnerable assets or stored payloads are not served.
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Verify the fix
- Confirm the running Cost Calculator Builder version is version 4.0.12 or newer, and record the patched version in the remediation ticket.
- Verify unauthorized users can no longer retrieve protected records, exports, form entries, tickets, user data, bookings, orders, or plugin configuration.
- Review web server, WordPress, security plugin, WAF, database, WooCommerce, booking/support, and application logs for exploitation attempts before and after the fix.
- Retest normal visitor, subscriber, customer, editor, administrator, checkout, form, API, booking, support ticket, import/export, backup/restore, snippet, or integration workflows to confirm expected behavior still works.
- Run a fresh Fixnx scan and document the public exposure state, patched version, log review, and any cleanup evidence.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-10865?
Cost Calculator Builder versions listed as affected should be reviewed: *-4.0.11.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.