CVE-2026-108384

Deferred Deferred - Pending Action

Code Execution via Malicious Avro Schema in dataclasses-avroschema

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: GitHub, Inc.

Description

dataclasses-avroschema generates Avro schemas from Python dataclasses, Pydantic models, and Faust Records and generates Python code from Avro schemas. From version 0.38.0 through 0.70.5, BaseGenerator.parse_fixed interpolates a fixed type's aliases value directly into a generated types.confixed annotation. A list is represented with quoted entries, but a bare string is emitted as an unquoted Python expression and evaluated when the generated module is imported, allowing arbitrary code execution from a crafted schema. Version 0.70.6 fixes the vulnerability by rejecting aliases values that are not lists.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-13

EPSS Evaluated

2026-10-18

NVD

CVE-2026-108384

EUVD

EUVD-2026-98981

Affected Vendors & Products

Vendor	Product	Version / Range
marcosschroh	dataclasses-avroschema	>= 0.38.0, < 0.70.6

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-94	The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

Attack-Flow Graph

Executive Summary

The vulnerability in dataclasses-avroschema allows arbitrary code execution when generating Python code from Avro schemas. Between versions 0.38.0 and 0.70.5, the BaseGenerator.parse_fixed function incorrectly handles fixed type aliases, treating bare strings as unquoted Python expressions. These expressions are evaluated during module import, enabling code execution from a maliciously crafted schema.

Detection Guidance

Check installed versions of dataclasses-avroschema with pip show dataclasses-avroschema. If the version is between 0.38.0 and 0.70.5, the system is vulnerable. Review generated Python modules for unquoted fixed type aliases in types.confixed annotations.

Impact Analysis

If you use affected versions of dataclasses-avroschema, an attacker could craft a malicious Avro schema that executes arbitrary code when your application imports the generated Python module. This could lead to data breaches, system compromise, or further network infiltration depending on the executed code's permissions.

Compliance Impact

This vulnerability could violate GDPR's integrity and confidentiality requirements by enabling unauthorized code execution and data access. For HIPAA, it risks exposing protected health information through arbitrary code execution. Compliance may require patching, auditing affected systems, and notifying regulators of potential data breaches.

Mitigation Strategies

Upgrade dataclasses-avroschema to version 0.70.6 or later. Review and sanitize any Avro schemas containing fixed type aliases to ensure they are lists, not bare strings.

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