CVE-2021-24884
The Formidable Form Builder WordPress plugin before 4.09.05 allows to inject certain HTML Tags like <audio>,<video>,<img>,<a> and<button>.This could allow an unauthenticated, remote attacker to exploit a HTML-injection byinjecting a malicous link. The HTML-injection may trick authenticated users to follow the link. If the Link gets clicked, Javascript code can be executed. The vulnerability is due to insufficient sanitization of the "data-frmverify" tag for links in the web-based entry inspection page of affected systems.
Leer descripción completaMostrar menos
A successful exploitation incomibantion with CSRF could allow the attacker to perform arbitrary actions on an affected system with the privileges of the user. These actions include stealing the users account by changing their password or allowing attackers to submit their own code through an authenticated user resulting in Remote Code Execution. If an authenticated user who is able to edit Wordpress PHP Code in any kind, clicks the malicious link, PHP code can be edited.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- Puntuación base: 9.6
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 3.13%
- Percentil entre todas las CVEs puntuadas: 87
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-79
- CWE-79, CWE-352
Referencias
- https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf
- https://github.com/Strategy11/formidable-forms/pull/335/files
- https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533
- https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf
- https://github.com/Strategy11/formidable-forms/pull/335/files
- https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533
JSON original (NVD)
Mostrar
{
"id": "CVE-2021-24884",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 6.8,
"accessVector": "NETWORK",
"vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:P",
"authentication": "NONE",
"integrityImpact": "PARTIAL",
"accessComplexity": "MEDIUM",
"availabilityImpact": "PARTIAL",
"confidentialityImpact": "PARTIAL"
},
"acInsufInfo": false,
"impactScore": 6.4,
"baseSeverity": "MEDIUM",
"obtainAllPrivilege": false,
"exploitabilityScore": 8.6,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": true
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 9.6,
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 6,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "contact@wpscan.com",
"affectedData": [
{
"vendor": "Unknown",
"product": "Formidable Form Builder – Contact Form, Survey & Quiz Forms Plugin for WordPress",
"versions": [
{
"status": "affected",
"version": "4.09.05",
"lessThan": "4.09.05",
"versionType": "custom"
}
]
}
]
}
],
"published": "2021-10-25T14:15:10.867",
"references": [
{
"url": "https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf",
"tags": [
"Exploit",
"Third Party Advisory"
],
"source": "contact@wpscan.com"
},
{
"url": "https://github.com/Strategy11/formidable-forms/pull/335/files",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "contact@wpscan.com"
},
{
"url": "https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533",
"tags": [
"Exploit",
"Third Party Advisory"
],
"source": "contact@wpscan.com"
},
{
"url": "https://github.com/S1lkys/XSS-in-Formidable-4.09.04/blob/main/XSS-in-Formidable-4.09.04.pdf",
"tags": [
"Exploit",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://github.com/Strategy11/formidable-forms/pull/335/files",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://wpscan.com/vulnerability/b57dacdd-43c2-48f8-ac1e-eb8306b22533",
"tags": [
"Exploit",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Secondary",
"source": "contact@wpscan.com",
"description": [
{
"lang": "en",
"value": "CWE-79"
}
]
},
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "CWE-79"
},
{
"lang": "en",
"value": "CWE-352"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "The Formidable Form Builder WordPress plugin before 4.09.05 allows to inject certain HTML Tags like <audio>,<video>,<img>,<a> and<button>.This could allow an unauthenticated, remote attacker to exploit a HTML-injection byinjecting a malicous link. The HTML-injection may trick authenticated users to follow the link. If the Link gets clicked, Javascript code can be executed. The vulnerability is due to insufficient sanitization of the \"data-frmverify\" tag for links in the web-based entry inspection page of affected systems. A successful exploitation incomibantion with CSRF could allow the attacker to perform arbitrary actions on an affected system with the privileges of the user. These actions include stealing the users account by changing their password or allowing attackers to submit their own code through an authenticated user resulting in Remote Code Execution. If an authenticated user who is able to edit Wordpress PHP Code in any kind, clicks the malicious link, PHP code can be edited."
},
{
"lang": "es",
"value": "El plugin Formidable Form Builder de WordPress versiones anteriores a 4.09.05, permite inyectar determinadas etiquetas HTML como ,,,<a rel=\"nofollow\"> y.Esto podría permitir a un atacante remoto no autenticado explotar una inyección HTML al inyectar un enlace malicioso. La inyección HTML puede engañar a usuarios autenticados para que sigan el enlace. Si se hace clic en el Enlace, es posible ejecutar código Javascript. La vulnerabilidad es debido a un saneamiento insuficiente de la etiqueta \"data-frmverify\" para los enlaces en la página de inspección de entrada de los sistemas afectados. Una explotación con éxito en combinación con CSRF podría permitir al atacante llevar a cabo acciones arbitrarias en un sistema afectado con los privilegios del usuario. Estas acciones incluyen el robo de la cuenta del usuario al cambiar su contraseña o permitir a atacantes enviar su propio código mediante un usuario autenticado, resultando en una ejecución de código remota. Si un usuario autenticado que es capaz de editar el código PHP de Wordpress en cualquier tipo, hace clic en el enlace malicioso, el código PHP puede ser editado</a>"
}
],
"lastModified": "2026-06-17T03:41:04.653",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:strategy11:formidable_form_builder:*:*:*:*:*:wordpress:*:*",
"vulnerable": true,
"matchCriteriaId": "F5D020F6-F06B-4437-8BBF-CCF40D95AC45",
"versionEndExcluding": "4.09.05"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "contact@wpscan.com"
}