{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2.9.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "967e616281ded1a0050d9102858ecd7dd7f66a41"
            }
          ],
          "repo": "https://github.com/shopperlabs/shopper",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-5vf4-452p-jjhf"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56831.json"
  },
  "details": "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.",
  "id": "CVE-2026-56831",
  "modified": "2026-09-18T03:30:47.683907208Z",
  "published": "2026-09-15T17:42:09.495Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/shopperlabs/shopper/releases/tag/v2.9.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56831.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/shopperlabs/shopper/security/advisories/GHSA-5vf4-452p-jjhf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56831"
    },
    {
      "type": "FIX",
      "url": "https://github.com/shopperlabs/shopper/commit/967e616281ded1a0050d9102858ecd7dd7f66a41"
    },
    {
      "type": "FIX",
      "url": "https://github.com/shopperlabs/shopper/pull/528"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Shopper: Negative discount values accepted and propagated through order calculation pipeline"
}