CVE-2026-27953 (GCVE-0-2026-27953)

Vulnerability from cvelistv5 – Published: 2026-03-19 20:23 – Updated: 2026-03-20 18:10
VLAI
Title
ormar has a Pydantic Validation Bypass via Kwargs Injection in Model Constructor
Summary
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. 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.
Severity
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-20 17:04 UTC
CWE
  • CWE-915 - Improperly Controlled Modification of Dynamically-Determined Object Attributes
  • CWE-20 - Improper Input Validation
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
ormar-orm ormar Affected: < 0.23.1
Create a notification for this product.
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