{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2023-26158",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2023-26158",
    "idYear": 2023,
    "status": "PUBLISHED",
    "publishedAt": "2023-12-08T05:00:01.350Z",
    "updatedAt": "2024-08-02T11:39:06.604Z",
    "importedAt": "2026-10-24T01:56:53.804Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": null,
      "summary": "All versions of the package mockjs are vulnerable to Prototype Pollution via the Util.extend function due to missing check if the attribute resolves to the object prototype. By adding or modifying attributes of an object prototype, it is possible to create attributes that exist on every object, or replace critical attributes with malicious ones. This can be problematic if the software depends on existence or non-existence of certain attributes, or uses pre-defined attributes of object prototype (such as hasOwnProperty, toString or valueOf).\r\rUser controlled inputs inside the extend() method of the Mock.Handler, Mock.Random, Mock.RE.Handler or Mock.Util, will allow an attacker to exploit this vulnerability.\r\r Workaround\r\rBy using a denylist of dangerous attributes, this weakness can be eliminated.\r\rAdd the following line in the Util.extend function:\r\rjs\rjs if ([\"__proto__\", \"constructor\", \"prototype\"].includes(name)) continue\r\r\rjs\r// src/mock/handler.js\rUtil.extend = function extend() {\r        var target = arguments[0] || {},\r            i = 1,\r            length = arguments.length,\r            options, name, src, copy, clone\r\r        if (length === 1) {\r            target = this\r            i = 0\r        }\r\r        for (; i < length; i++) {\r            options = arguments[i]\r            if (!options) continue\r\r            for (name in options) {\r            if ([\"__proto__\", \"constructor\", \"prototype\"].includes(name)) continue\r                src = target[name]\r                copy = options[name]\r\r                if (target === copy) continue\r                if (copy === undefined) continue\r\r                if (Util.isArray(copy) || Util.isObject(copy)) {\r                    if (Util.isArray(copy)) clone = src && Util.isArray(src) ? src : []\r                    if (Util.isObject(copy)) clone = src && Util.isObject(src) ? src : {}\r\r                    target[name] = Util.extend(clone, copy)\r                } else {\r                    target[name] = copy\r                }\r            }\r        }\r\r        return target\r    }\r",
      "affected": [
        {
          "vendor": "n/a",
          "product": "mockjs",
          "versions": [
            {
              "version": "0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "*"
            }
          ]
        }
      ]
    }
  }
}