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CVE-2026-27953

CRITICAL CVSS 3.1: 9.8 EPSS 0.42%
Updated Mar 27, 2026
Python
Parameter Value
CVSS 9.8 (CRITICAL)
Affected Versions before 0.23.1
Fixed In 0.23.1
Type CWE-915, CWE-20 (Improper Input Validation)
Vendor Python
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Collerek Ormar
cpe:2.3:a:collerek:ormar:*:*:*:*:*:python:*:*
0.23.1