CVE-2018-17175 : What You Need to Know

The Python marshmallow library versions before 2.15.1 and 3.x before 3.0.0b9 had a behavior where the "only" option in the schema could expose all fields instead of hiding them when an empty list was interpreted as the absence of the "only" option. This could lead to unintended exposure of fields under specific conditions.

Understanding CVE-2018-17175

This CVE pertains to a vulnerability in the Python marshmallow library that could result in exposing fields that were intended to be hidden.

What is CVE-2018-17175?

In versions prior to 2.15.1 and 3.x before 3.0.0b9 of the marshmallow library, an issue existed where using the "only" option in the schema could lead to all fields being exposed instead of hidden when an empty list was treated as no "only" option.

The Impact of CVE-2018-17175

The vulnerability could potentially expose sensitive data that was meant to be hidden, compromising the confidentiality of information.

Technical Details of CVE-2018-17175

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability allowed requests that were supposed to hide all fields to inadvertently expose all fields under specific circumstances.

Affected Systems and Versions

Python marshmallow library versions before 2.15.1
Python marshmallow library 3.x before 3.0.0b9

Exploitation Mechanism

The issue occurred when the schema was dynamically filtered using the "only" option and a user role had an empty value for "only."

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of this vulnerability.

Immediate Steps to Take

Upgrade to Python marshmallow library versions 2.15.1 or higher for versions before 3.x
Upgrade to Python marshmallow library version 3.0.0b9 or higher for 3.x

Long-Term Security Practices

Regularly review and update access control configurations
Conduct security audits to identify similar vulnerabilities

Patching and Updates

Apply patches provided by the Python marshmallow library to fix the vulnerability