CVE-2021-39194 : Exploit Details and Defense Strategies

Kaml is an open-source YAML format implementation with support for kotlinx.serialization. A vulnerability in versions prior to 0.35.2 could lead to a denial of service attack due to endless looping while parsing YAML input.

Understanding CVE-2021-39194

In this section, we will delve into the details of the CVE-2021-39194 vulnerability.

What is CVE-2021-39194?

CVE-2021-39194 is a vulnerability in kaml versions less than 0.35.2 that allows attackers to cause endless loops in applications parsing YAML input, leading to denial of service.

The Impact of CVE-2021-39194

The impact of this vulnerability is outlined below:

CVSS Base Score: 4.3 (Medium)
Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
Availability Impact: Low

Technical Details of CVE-2021-39194

Let's explore the technical aspects of CVE-2021-39194.

Vulnerability Description

The vulnerability in kaml versions prior to 0.35.2 allows for endless looping while processing YAML input, potentially leading to resource starvation and denial of service.

Affected Systems and Versions

Affected Product: kaml
Vendor: charleskorn
Affected Versions: < 0.35.2

Exploitation Mechanism

The vulnerability can be exploited by providing arbitrary YAML input using polymorphic serialization with the default tagged polymorphism style, triggering an endless loop.

Mitigation and Prevention

Learn how to mitigate the risks associated with CVE-2021-39194.

Immediate Steps to Take

Consider the following actions to mitigate the CVE-2021-39194 vulnerability:

Upgrade to version 0.35.3 or later.
Avoid using polymorphic serialization with the default tagged polymorphism style.

Long-Term Security Practices

To enhance long-term security, consider the following practices:

Regularly update kaml to the latest versions.
Implement proper input validation mechanisms.

Patching and Updates

Ensure that you promptly apply patches and updates to address vulnerabilities like CVE-2021-39194.