{
  "affected": [
    {
      "database_specific": {
        "unresolved_ranges": [
          {
            "events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "2025-09-13"
              }
            ]
          }
        ]
      }
    }
  ],
  "details": "A type confusion vulnerability exists in the handling of the string addition (+) operation within the QuickJS engine.\n\n  *  The code first checks if the left-hand operand is a string.\n\n\n  *  It then attempts to convert the right-hand operand to a primitive value using JS_ToPrimitiveFree. This conversion can trigger a callback (e.g., toString or valueOf).\n\n\n  *  During this callback, an attacker can modify the type of the left-hand operand in memory, changing it from a string to a different type (e.g., an object or an array).\n\n\n  *  The code then proceeds to call JS_ConcatStringInPlace, which still treats the modified left-hand value as a string.\n\n\nThis mismatch between the assumed type (string) and the actual type allows an attacker to control the data structure being processed by the concatenation logic, resulting in a type confusion condition. This can lead to out-of-bounds memory access, potentially resulting in memory corruption and arbitrary code execution in the context of the QuickJS runtime.",
  "id": "CVE-2025-62494",
  "modified": "2026-03-10T21:49:58.318853955Z",
  "published": "2025-10-16T16:15:39.943Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://bellard.org/quickjs/Changelog"
    },
    {
      "type": "REPORT",
      "url": "https://issuetracker.google.com/434193023"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}