CVE-2026-56831

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.

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 37% of CVEs (scores of 2026-10-25)

CWE

CWE-20

Published

2026-09-15

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

References

• https://github.com/shopperlabs/shopper/commit/967e616281ded1a0050d9102858ecd7dd7f66a41
• https://github.com/shopperlabs/shopper/pull/528
• https://github.com/shopperlabs/shopper/releases/tag/v2.9.0
• https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf
• https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf

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