FKIE_CVE-2026-4257

Vulnerability from fkie_nvd - Published: 2026-03-30 22:16 - Updated: 2026-04-01 14:24
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
The Contact Form by Supsystic plugin for WordPress is vulnerable to Server-Side Template Injection (SSTI) leading to Remote Code Execution (RCE) in all versions up to, and including, 1.7.36. This is due to the plugin using the Twig `Twig_Loader_String` template engine without sandboxing, combined with the `cfsPreFill` prefill functionality that allows unauthenticated users to inject arbitrary Twig expressions into form field values via GET parameters. This makes it possible for unauthenticated attackers to execute arbitrary PHP functions and OS commands on the server by leveraging Twig's `registerUndefinedFilterCallback()` method to register arbitrary PHP callbacks.
References
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/contact-form-by-supsystic/tags/1.7.36/modules/forms/views/forms.php#L323
security@wordfence.comhttps://plugins.trac.wordpress.org/changeset/3491826/contact-form-by-supsystic
security@wordfence.comhttps://www.wordfence.com/threat-intel/vulnerabilities/id/415c9658-bfb2-453b-a697-c63c08b0ca61?source=cve
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Contact Form by Supsystic plugin for WordPress is vulnerable to Server-Side Template Injection (SSTI) leading to Remote Code Execution (RCE) in all versions up to, and including, 1.7.36. This is due to the plugin using the Twig `Twig_Loader_String` template engine without sandboxing, combined with the `cfsPreFill` prefill functionality that allows unauthenticated users to inject arbitrary Twig expressions into form field values via GET parameters. This makes it possible for unauthenticated attackers to execute arbitrary PHP functions and OS commands on the server by leveraging Twig\u0027s `registerUndefinedFilterCallback()` method to register arbitrary PHP callbacks."
    },
    {
      "lang": "es",
      "value": "El plugin Contact Form by Supsystic para WordPress es vulnerable a la inyecci\u00f3n de plantillas del lado del servidor (SSTI) lo que lleva a la ejecuci\u00f3n remota de c\u00f3digo (RCE) en todas las versiones hasta la 1.7.36, inclusive. Esto se debe a que el plugin utiliza el motor de plantillas Twig \u0027Twig_Loader_String\u0027 sin sandboxing, combinado con la funcionalidad de precarga \u0027cfsPreFill\u0027 que permite a los usuarios no autenticados inyectar expresiones Twig arbitrarias en los valores de los campos del formulario a trav\u00e9s de par\u00e1metros GET. Esto hace posible que atacantes no autenticados ejecuten funciones PHP y comandos del sistema operativo arbitrarios en el servidor aprovechando el m\u00e9todo \u0027registerUndefinedFilterCallback()\u0027 de Twig para registrar retrollamadas PHP arbitrarias."
    }
  ],
  "id": "CVE-2026-4257",
  "lastModified": "2026-04-01T14:24:02.583",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "security@wordfence.com",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-03-30T22:16:20.313",
  "references": [
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/contact-form-by-supsystic/tags/1.7.36/modules/forms/views/forms.php#L323"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/changeset/3491826/contact-form-by-supsystic"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/415c9658-bfb2-453b-a697-c63c08b0ca61?source=cve"
    }
  ],
  "sourceIdentifier": "security@wordfence.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-94"
        }
      ],
      "source": "security@wordfence.com",
      "type": "Primary"
    }
  ]
}


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