CVE-2026-56831: Shopperlabs Shopper

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Shopper is a Headless e-commerce Admin Panel. Prior to 2.9.0, the /cpanel/discounts administrative interface accepts negative fixed_amount discount values, persists them in sh_discounts, and passes them through vendor/shopper/cart/src/Discounts/DiscountCalculator.php and vendor/shopper/cart/src/Pipelines/Calculate.php without enforcing a positive-value invariant. Because the calculation subtracts discountTotal from the subtotal, a negative discount increases the resulting order total instead of reducing it. Malformed discount records can therefore cause incorrect pricing and financial data integrity failures, although the advisory does not establish a customer-facing exploitation path. This issue is fixed in version 2.9.0.

Affected products

• Shopperlabs Shopper: before 2.9.0 (fixed in 2.9.0)

Published 2026-09-15. Last modified 2026-09-30.