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CVE-2026-84939

Estado: AnalizadaCrítica (9.1)—

Path traversal vulnerability in Apache FreeMarker template loading mechanism, if the attacker can specify an arbitrary malformed locale identifier to FreeMarker, and the localized lookup configuration setting is enabled (it's by default enabled).

This issue affects Apache FreeMarker from 2.2.0 through 2.3.34.

Users are recommended to upgrade to version 2.3.35. Disabling localized lookup in previous versions also mitigates this.

Note that even in versions affected by this vulnerability, the files that can be loaded remain restricted by the TemplateLoader that FreeMarker is configured to use.

Leer descripción completaMostrar menos

In particular, FileTemplateLoader prevents attempts to traverse outside the baseDir specified in its constructor. Other TemplateLoader implementations may allow access outside their designated base directory, but they are still constrained by the underlying storage mechanism—for example, a loader wrapping a Java class loader can only access resources that the class loader can load, while one wrapping a web application context can only access resources available through that context.

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.

Path traversal en mecanismo de carga de plantillas FreeMarker (AV:N/PR:N/UI:N) permite a atacante remoto leer archivos arbitrarios dentro del directorio base configurado (CWE-23, impacto C:H).

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

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Apache — Freemarker

CWE

Referencias

JSON original (NVD)

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  "id": "CVE-2026-84939",
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  "metrics": {
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  "published": "2026-09-10T06:17:06.460",
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    }
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  "lastModified": "2026-09-11T13:06:56.423",
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