CVE-2026-27206: Zumba/json serializer Zumba Json Serializer Has A Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-v7m3-fpcr-h7m2",
  "modified" : "2026-02-23T22:28:11Z",
  "published" : "2026-02-19T22:05:40Z",
  "aliases" : [ "CVE-2026-27206" ],
  "summary" : "Zumba Json Serializer has a potential PHP Object Injection via Unrestricted @type in unserialize()",
  "details" : "### Description\n\nThe `zumba/json-serializer` library allows deserialization of PHP objects from JSON using a special `@type` field.\n\nPrior to version 3.2.3, the deserializer would instantiate any class specified in the `@type` field without restriction. When processing untrusted JSON input, this behavior may allow an attacker to instantiate arbitrary classes available in the application.\n\nIf a vulnerable application passes attacker-controlled JSON into JsonSerializer::unserialize() and contains classes with dangerous magic methods (such as `__wakeup()` or `__destruct()`), this may lead to PHP Object Injection and potentially Remote Code Execution (RCE), depending on available gadget chains in the application or its dependencies.\n\nThis behavior is similar in risk profile to PHP's native `unserialize()` when used without the `allowed_classes` restriction.\n\n### Impact\n\nThis vulnerability allows instantiation of arbitrary PHP classes via the `@type` field when deserializing JSON.\n\nApplications are impacted only if:\n* Untrusted or attacker-controlled JSON is passed into `JsonSerializer::unserialize()`, and\n* The application or its dependencies contain classes that can be leveraged as a gadget chain.\n\nSuccessful exploitation may lead to:\n* Arbitrary code execution\n* Data exfiltration\n* File manipulation\n* Denial of service\n\nApplications that only deserialize trusted data are not affected.\n\n### Patches\n\nThis issue is mitigated in version 3.2.3.\n\nVersion 3.2.3 introduces the method: `setAllowedClasses(?array $allowedClasses)`\n\nThis allows applications to restrict which classes may be instantiated during deserialization, similar to PHP's native `unserialize()` `allowed_classes` option.\n\nUsers should upgrade to version 3.2.3 or later and configure an appropriate class allowlist.\n\n### Workarounds\n\nIf upgrading is not immediately possible, applications should ensure that:\n* `JsonSerializer::unserialize()` is never called on untrusted or attacker-controlled JSON.\n* JSON input is validated and sanitized before deserialization.\n* Object instantiation via `@type` is disabled in application logic where possible.\n\nAfter upgrading, users can mitigate risk by explicitly configuring:\n\n```php\n$serializer->setAllowedClasses([]);\n```\n\nto disable all object instantiation, or by providing a strict allowlist of safe classes.\n\n### References\n\n* CWE-502: https://cwe.mitre.org/data/definitions/502.html\n* PHP `unserialize()` documentation: https://www.php.net/manual/en/function.unserialize.php\n* OWASP PHP Object Injection: https://owasp.org/www-community/vulnerabilities/PHP_Object_Injection",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "zumba/json-serializer"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.2.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/zumba/json-serializer/security/advisories/GHSA-v7m3-fpcr-h7m2"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27206"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/zumba/json-serializer/commit/bf26227879adefce75eb9651040d8982be97b881"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/zumba/json-serializer"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/zumba/json-serializer/releases/tag/3.2.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-502" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-19T22:05:40Z",
    "nvd_published_at" : "2026-02-21T07:16:11Z"
  }
}