CVE-2026-56831 Shopper: Negative discount values accepted and propagated through order calculation pipeline

Shopper is a Headless e-commerce Admin Panel. Prior to 2.9.0, the /cpanel/discounts administrative interface accepts negative fixedamount discount values, persists them in shdiscounts, and passes them through vendor/shopper/cart/src/Discounts/DiscountCalculator.php and...