CVE-2026-47741: shopper/framework Race Condition On Discount.usage_limit Allows Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9rh9-hf3w-9fgg",
  "modified" : "2026-06-08T20:07:26Z",
  "published" : "2026-05-18T16:37:20Z",
  "aliases" : [ "CVE-2026-47741" ],
  "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",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "shopper/cart"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.8.0"
      } ]
    } ]
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-18T16:37:20Z",
    "nvd_published_at" : "2026-05-29T19:16:25Z"
  }
}