CVE-2024-24821: A Critical Alert for Composer’s PHP Dependency Management

In the bustling world of web development, the Composer tool has emerged as a cornerstone for managing dependencies in PHP projects. By simplifying the inclusion and update of libraries, Composer has become indispensable for developers looking to streamline their workflows. However, the discovery of a vulnerability, identified as CVE-2024-24821, casts a shadow over Composer’s reliability, exposing users to potential code execution and privilege escalation threats.


CVE-2024-24821 carries a CVSS score of 8.8, marking it as a high-severity issue. This vulnerability stems from the way Composer includes several files from the local working directory during its invocation. This seemingly innocuous process opens the door to arbitrary code execution under certain conditions. Specifically, if Composer is run in a directory containing tampered files, attackers can exploit this vulnerability to execute malicious code, potentially leading to local privilege escalation, lateral user movement, or further malicious activities.

The vulnerability is particularly concerning due to the widespread practice of invoking Composer across various environments. It affects all Composer Command Line Interface (CLI) commands, including the crucial `composer.phar`’s self-update functionality. High-risk scenarios include running Composer with `sudo` privileges, executing Composer in pipelines on untrusted projects, and using Composer in shared environments where multiple developers interact with the same project.

Composer versions from 2.0 up to but not including 2.2.23, as well as versions from 2.3 up to but not including 2.7, are vulnerable to CVE-2024-24821. The developers behind Composer have acted swiftly to address this issue, releasing patches in versions 2.7.0 and 2.2.23. Users are urged to upgrade to these patched versions at their earliest convenience to protect their projects from potential exploitation.

For those unable to immediately update to the patched versions, several mitigation strategies are recommended to safeguard against the vulnerability. Key among these is the removal of `sudo` privileges for running Composer, significantly reducing the risk of root privilege escalation. Additionally, caution is advised when running Composer in untrusted directories. Verifying the contents of `vendor/composer/InstalledVersions.php` and `vendor/composer/installed.php` for untrusted code is a prudent step. In case of suspicion, a reset of these files can be performed using the following commands:

rm vendor/composer/installed.php vendor/composer/InstalledVersions.php
composer install –no-scripts –no-plugins

This approach ensures that any potentially malicious modifications are removed, reinstating a safer development environment.

While Composer continues to play a vital role in PHP development, this incident underscores the importance of maintaining a vigilant posture towards security. Regularly updating dependencies, adhering to best practices for secure coding, and staying informed about vulnerabilities are essential steps in navigating the complex landscape of software development securely.