CVE-2026-8134

Estado: AnalizadaCrítica (9.4)—

Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H Thanks Yonatan Drori (Tenzai) for reporting.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Puntuación base: 9.4

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 1.11%
Percentil entre todas las CVEs puntuadas: 65
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).

🎯 Técnicas ATT&CK

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

ExplotaciónT1210 Exploitation of Remote Serviceslateral movement90 %
Impacto principalT1005 Data from Local Systemcollection85 %
Impacto secundarioT1505.003 Web Shellpersistence80 %

AV:N + PR:H + acceso a servicios remotos que requieren privilegios elevados. Path traversal + LFI + RCE autenticada en CMS (lectura de archivos + ejecución de PHP inyectado en imágenes).

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

Disable or Remove Feature or Program Vulnerability Scanning User Account Management Threat Intelligence Program Privileged Account Management Network Segmentation

Tecnologías afectadas (1)

Concretecms — Concrete CMS

CWE

CWE-23, CWE-98, CWE-434

Referencias

https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes

JSON original (NVD)

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      "value": "Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H   Thanks Yonatan Drori (Tenzai) for reporting."
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      "value": "Concrete CMS 9.5.0 y versiones anteriores no sanea las secuencias de salto de ruta en el campo ptComposerFormLayoutSetControlCustomTemplate al guardar diseños de formularios de compositor de tipo de página. Un administrador malicioso autenticado con derechos de edición de formularios de compositor puede explotar esto para incluir archivos legibles arbitrarios en el servidor. Combinado con la validación solo por extensión del cargador de archivos (que permite código PHP en archivos guardados con extensiones de imagen como .png), esto puede resultar en ejecución remota de código autenticada. El equipo de seguridad de Concrete CMS otorgó a esta vulnerabilidad una puntuación CVSS v.4.0 de 9.4 con el vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H. Gracias a Yonatan Drori (Tenzai) por informar."
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