FKIE_CVE-2026-46625

Vulnerability from fkie_nvd - Published: 2026-06-10 22:16 - Updated: 2026-06-11 17:16
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
JavaScript Cookie is a JavaScript API for handling cookies, client-side. Prior to version 3.0.7, js-cookie's internal assign() helper copies properties with for...in + plain assignment. When the source object is produced by JSON.parse, the JSON object's "__proto__" member is an own enumerable property, so the for…in enumerates it and the target[key] = source[key] write triggers the Object.prototype.__proto__ setter on the fresh target ({}). The result is a per-instance prototype hijack: Object.prototype itself is untouched, but the merged attributes object now inherits attacker-controlled keys. Because the consuming set() function then enumerates the merged object with another for...in, every key the attacker placed on the polluted prototype lands in the resulting Set-Cookie string as an attribute pair. The attacker can set domain=, secure=, samesite=, expires=, and path= on cookies whose attributes the developer thought were locked down. This issue has been patched in version 3.0.7.
References
security-advisories@github.comhttps://github.com/js-cookie/js-cookie/commit/eb3c40e89731e99b8970faaf35ddad249c6c0020
security-advisories@github.comhttps://github.com/js-cookie/js-cookie/releases/tag/v3.0.7
security-advisories@github.comhttps://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "JavaScript Cookie is a JavaScript API for handling cookies, client-side. Prior to version 3.0.7, js-cookie\u0027s internal assign() helper copies properties with for...in + plain assignment. When the source object is produced by JSON.parse, the JSON object\u0027s \"__proto__\" member is an own enumerable property, so the for\u2026in enumerates it and the target[key] = source[key] write triggers the Object.prototype.__proto__ setter on the fresh target ({}). The result is a per-instance prototype hijack: Object.prototype itself is untouched, but the merged attributes object now inherits attacker-controlled keys. Because the consuming set() function then enumerates the merged object with another for...in, every key the attacker placed on the polluted prototype lands in the resulting Set-Cookie string as an attribute pair. The attacker can set domain=, secure=, samesite=, expires=, and path= on cookies whose attributes the developer thought were locked down. This issue has been patched in version 3.0.7."
    }
  ],
  "id": "CVE-2026-46625",
  "lastModified": "2026-06-11T17:16:34.250",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-10T22:16:59.613",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/js-cookie/js-cookie/commit/eb3c40e89731e99b8970faaf35ddad249c6c0020"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/js-cookie/js-cookie/releases/tag/v3.0.7"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/js-cookie/js-cookie/security/advisories/GHSA-qjx8-664m-686j"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-1321"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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