CVE-2026-31867: Craft Commerce Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vff3-pqq8-4cpq",
  "modified" : "2026-03-11T20:57:29Z",
  "published" : "2026-03-10T18:24:49Z",
  "aliases" : [ "CVE-2026-31867" ],
  "summary" : "Craft Commerce: Potential IDOR in Commerce carts",
  "details" : "An Insecure Direct Object Reference (IDOR) vulnerability exists in Craft Commerce’s cart functionality that allows users to hijack any shopping cart by knowing or guessing its 32-character number. This vulnerability enables the takeover of shopping sessions and potential exposure of PII.\n\n## Vulnerability Details\n\n### Root Cause\n\nThe `CartController` accepts a user-supplied `number` parameter to load and modify shopping carts. No ownership validation is performed - the code only checks if the order exists and is incomplete, not whether the requester has authorization to access it.\n\n```php\n// CartController.php:374-389 - actionLoadCart()\npublic function actionLoadCart(): ?Response\n{\n    $number = $this->request->getParam('number');\n\n    if ($number === null) {\n        return $this->asFailure(Craft::t('commerce', 'A cart number must be specified.'));\n    }\n\n    // No ownership check - returns any cart to any requester\n    $cart = Order::find()->number($number)->isCompleted(false)->one();\n\n    // Cart is loaded into attacker's session without authorization\n    ...\n}\n```\n\n```php\n// CartController.php:606-616 - _getCart()\n$orderNumber = $this->request->getBodyParam('number');\nif ($orderNumber) {\n    // Same issue - no ownership validation\n    $cart = Order::find()->number($orderNumber)->isCompleted(false)->one();\n    // Returns cart to any requester who knows the number\n}\n```\n---\n\n## Attack Scenario\n\n### Prerequisites\n- Target Craft Commerce installation with active shopping carts\n- Knowledge of a victim’s cart number (32-character hex string)\n\n### Cart Number Acquisition Vectors\n\n1. **Referrer Header Leakage**: Cart URLs shared externally expose the number\n2. **Browser History**: Accessible on shared/compromised devices\n3. **Proxy/WAF Logs**: Cart numbers logged in URL parameters\n4. **Social Engineering**: Support tickets, screenshots containing cart URLs\n5. **Brute Force**: While impractical for random targeting, feasible for targeted attacks against recently-created carts\n\n---",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/commerce"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "5.0.0"
      }, {
        "fixed" : "5.6.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "craftcms/commerce"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.11.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/commerce/security/advisories/GHSA-vff3-pqq8-4cpq"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31867"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/craftcms/commerce/pull/4207"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/craftcms/commerce"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-10T18:24:49Z",
    "nvd_published_at" : "2026-03-11T18:16:25Z"
  }
}