CVE-2026-27953

Estado: AnalizadaCrítica (9.8)—

ormar is a async mini ORM for Python. Versions 0.23.0 and below are vulnerable to Pydantic validation bypass through the model constructor, allowing any unauthenticated user to skip all field validation by injecting "__pk_only__": true into a JSON request body. By injecting "__pk_only__": true into a JSON request body, an unauthenticated attacker can skip all field validation and persist unvalidated data directly to the database. A secondary __excluded__ parameter injection uses the same pattern to selectively nullify arbitrary model fields (e.g., email or role) during construction.

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This affects ormar's canonical FastAPI integration pattern recommended in its official documentation, enabling privilege escalation, data integrity violations, and business logic bypass in any application using ormar.Model directly as a request body parameter. This issue has been fixed in version 0.23.1.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 9.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.91%
Percentil entre todas las CVEs puntuadas: 58
Fecha de la puntuación: 5/10/2026

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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access95 %
Impacto principalT1565.003 Runtime Data Manipulationimpact90 %
Impacto secundarioT1068 Exploitation for Privilege Escalationprivilege escalation85 %

Vulnerabilidad de validación en ORM expuesto vía API REST (AV:N, PR:N, UI:N). Inyección de parámetros bypassa validación Pydantic, persistiendo datos malformados en BD (T1565.003), escalando privilegios (T1068) y suplantando roles (T1078.001).

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

Network Segmentation Application Isolation and Sandboxing Exploit Protection Update Software Vulnerability Scanning Threat Intelligence Program

Tecnologías afectadas (1)

Collerek — Ormar

CWE

CWE-20, CWE-915

Referencias

JSON original (NVD)

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