In this long-read post, we will dive deep into the Yii 2 security vulnerability titled CVE-2024-58136. This vulnerability, known to affect Yii 2 versions before 2..52, has caused serious security concerns within the programmer community as it has been actively exploited in the wild between February and April of 2025. Specifically, this security issue is associated with how an "__class" array key mishandles the attaching of behavior in the Yii 2 framework – a regression of CVE-2024-499. Throughout the article, we will discuss code snippets, exploit details, and provide links to the corresponding original references.

An Overview of Yii 2

Yii 2 is a widely popular high-performance PHP framework that assists developers in creating web applications swiftly and efficiently. The framework is incredibly flexible, allowing programmers to easily adjust the source code to suit the specific requirements of their projects. One essential feature of Yii 2 is its ability to manage behavior attachments, an important aspect of creating highly functional web applications.

Original Reference

For those who wish to dig further into this vulnerability's details, here is the link to the official CVE document: CVE-2024-58136

Understanding the Vulnerability

The issue of CVE-2024-58136 is a regression from the previous vulnerability, CVE-2024-499. As a result, this security vulnerability is directly linked to how Yii 2 handles behavior attachments. By exploiting this regression, a malicious user can tamper with the system behavior and may even take control of the website leading to various potential threats such as unauthorized data access, falsification, or damaging critical data components.

Code Snippet

Let's take a look at a sample code snippet illustrating the mishandling of '__class' array key in Yii 2 behavior attachments:

<?php
// An example Behavior.php file
class MyBehavior extends \yii\base\Behavior
{
    public function events()
    {
        return [
            ActiveRecord::EVENT_BEFORE_VALIDATE => 'beforeValidate',
        ];
    }

    public function beforeValidate($event)
    {
        // ... behavior code ...
    }
}

// Inside the Model.php constructor
public function __construct($config = [])
{
    $this->attachBehavior('MyBehavior', [
        '__class' => MyBehavior::class,
        // ... additional configurations ...
    ]);
    parent::__construct($config);
}
?>

In this example, we can observe the addition of a behavior attachment in the model's constructor. The vulnerability in question stems directly from calling the 'attachBehavior()' function with an '__class' array key.

Exploit Details

As previously mentioned, a knowledgeable attacker can take advantage of this vulnerability to modify the behavior of a Yii 2 application. Some specific consequences include unauthorized data access, code execution, data corruption, and the ability to launch further attacks on other parts of the system.

Due to this security threat's immense impact on Yii 2 applications, it is absolutely essential to ensure that any projects using Yii 2 are updated to the latest version promptly to patch this critical security vulnerability.

How to Remediate

To mitigate the risk and prevent this vulnerability from affecting Yii 2 applications, it is crucial to update to the latest Yii 2 version, 2..52 or later. By doing so, the vulnerability will be patched, and web applications developed with the Yii 2 framework will be shielded against any potential exploits. You can find the latest Yii 2 release at the following link: Yii 2 Releases

Conclusion

As a Yii 2 developer, one must always be aware of any security vulnerabilities that could impact their applications. The information detailed in this article on CVE-2024-58136 should enable developers to identify and understand the implications of this security issue, as well as provide guidance on how to keep their Yii 2 applications up-to-date and secure. Stay vigilant, and keep on coding!

Timeline

Published on: 04/10/2025 03:15:17 UTC
Last modified on: 04/28/2025 18:46:35 UTC