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CVE-2026-8203

Estado: AnalizadaAlta (7.3)—

Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Alfin Joseph for reporting.

CVSS

Probabilidad de explotación (EPSS)

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

XSS almacenado en parámetro height sin sanitización (CWE-79). Ejecuta JavaScript en navegador de visitantes (T1059.007). Permite robo de sesiones y credenciales (T1539).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Restrict Web-Based ContentUser TrainingUpdate SoftwareMulti-factor AuthenticationExecution PreventionBehavior Prevention on Endpoint

Tecnologías afectadas (1)

Concretecms — Concrete CMS

CWE

Referencias

JSON original (NVD)

Mostrar
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  "published": "2026-05-21T21:16:33.380",
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      "value": "Concrete CMS 9.5.0 and below has Stored XSS on the height parameter. The controller does not validate or sanitize $height. Any user with editor privileges can inject malicious JavaScript that executes in the context of any visitor's browser, potentially leading to session hijacking, credential theft, or other malicious actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 7.3 with vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Alfin Joseph for reporting."
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      "value": "Concrete CMS 9.5.0 y versiones anteriores tiene una XSS Almacenada en el parámetro height. El controlador no valida ni sanea $height. Cualquier usuario con privilegios de editor puede inyectar JavaScript malicioso que se ejecuta en el contexto del navegador de cualquier visitante, lo que podría llevar al secuestro de sesión, robo de credenciales u otras acciones maliciosas. El equipo de seguridad de Concrete CMS otorgó a esta vulnerabilidad una puntuación CVSS v.4.0 de 7.3 con el vector CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Gracias a Alfin Joseph por el informe."
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