{"id":"GHSA-9rh9-hf3w-9fgg","summary":"shopper/framework: Race condition on Discount.usage_limit allows silent over-redemption","details":"## Impact\n\n`CreateOrderFromCartAction::execute` previously created the `Order` row before checking and incrementing the discount's `total_use` counter. Under concurrent checkout pressure (Black Friday, flash sale, viral coupon), the global `usage_limit` was silently exceeded: orders were committed with the discount fully applied to `price_amount` while the counter blocked at `usage_limit`. The merchant had no signal that an over-redemption had occurred.\n\nA second related bug: `usage_limit_per_user` was effectively a no-op because the counter it relied on (`DiscountDetail.total_use`) was never incremented anywhere in the codebase. The per-user check therefore always saw `0` uses and validation passed regardless of how many times the same customer had previously redeemed the coupon. For `eligibility = Everyone` the per-user limit could not fire at all because the underlying `DiscountDetail` row only exists for `eligibility = Customers`.\n\nDirect financial loss: each over-redemption is a discount the merchant did not intend to grant.\n\n## Patches\n\nFixed in `v2.8.0`. `CreateOrderFromCartAction` now:\n\n- Reserves the discount slot atomically before the order row is created, inside the same `DB::transaction` with `lockForUpdate` and a compare-and-swap on `total_use`.\n- Throws `DiscountLimitReachedException::global` and rolls back the transaction when the global limit was exhausted between cart validation and commit. No order is committed.\n- Throws `DiscountLimitReachedException::perUser` and rolls back when the discount is restricted to one use per customer and the customer has already redeemed it.\n- Snapshots `discount_id`, `discount_code`, `discount_type`, `discount_value_at_apply` and `discount_currency_code` onto the `orders` table for resilience against later discount edits or deletions.\n\n`DiscountValidator` was updated to perform the same Order-based per-user check at cart-apply time so the rejection is surfaced before checkout.\n\nUpgrade via:\n\n`composer require shopper/cart:^2.8 shopper/core:^2.8`\n`php artisan migrate`\n\n## Workarounds\n\nNone. Upgrade to `v2.8.0`.\n\n## Resources\n\n- Issue: https://github.com/shopperlabs/shopper/issues/510\n- Pull request: https://github.com/shopperlabs/shopper/pull/511\n- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization","aliases":["CVE-2026-47741"],"modified":"2026-09-10T03:50:46.608303946Z","published":"2026-05-18T16:37:20Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-05-18T16:37:20Z","nvd_published_at":"2026-05-29T19:16:25Z","cwe_ids":["CWE-362"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/shopperlabs/shopper/security/advisories/GHSA-9rh9-hf3w-9fgg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47741"},{"type":"WEB","url":"https://github.com/shopperlabs/shopper/issues/510"},{"type":"WEB","url":"https://github.com/shopperlabs/shopper/pull/511"},{"type":"WEB","url":"https://github.com/shopperlabs/shopper/commit/fcd0c5920588702df5b874f432b1042abd77a50b"},{"type":"PACKAGE","url":"https://github.com/shopperlabs/shopper"},{"type":"WEB","url":"https://github.com/shopperlabs/shopper/releases/tag/v2.8.0"}],"affected":[{"package":{"name":"shopper/cart","ecosystem":"Packagist","purl":"pkg:composer/shopper/cart"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.8.0"}]}],"versions":["v2.6.0","v2.6.1","v2.6.2","v2.6.3","v2.6.4","v2.7.0","v2.7.1","v2.7.2","v2.7.3"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-9rh9-hf3w-9fgg/GHSA-9rh9-hf3w-9fgg.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"}]}