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Mitigation Instructions for CVE-2018-15133

Mitigation Instructions for CVE-2018-15133

SUBJECT: Mitigation for Laravel Deserialization of Untrusted Data Vulnerability (CVE-2018-15133)

TECH STACK: Laravel Framework

DATE(S) ISSUED: 08/09/2018

NVD Last Modified: 01/16/2024



This vulnerability affects Laravel Framework versions 5.5.40 and below, and 5.6.0 through 5.6.29. CVE-2018-15133 exploits a weakness in Laravel's deserialization process. Unsanitized user input, particularly the X-XSRF-TOKEN, can be crafted to contain malicious code. If this code is then deserialized and executed, the attacker gains remote code execution (RCE) capabilities on your server, potentially compromising data, installing backdoors, or launching further attacks.

 An attacker with successful exploitation can gain complete control of your server, leading to data breaches, financial losses, and reputational harm.


  • Upgrade to Laravel version 5.6.30 or later. This version includes a fix for the vulnerability.


  • Rotate your application key: Even if you upgrade to a fixed version, it is recommended to rotate your application key as an additional precaution.
  • Implement input validation and sanitization: Validate and sanitize all user-provided input, especially the X-XSRF-TOKEN value, to prevent attackers from injecting malicious data.
  • Enable Content Security Policy (CSP): CSP can help prevent attackers from loading malicious scripts onto your website.
  • Keep Laravel and its dependencies up to date:  This will help to ensure that you are protected against the latest vulnerabilities.

Confirmation & Additional Information:

  • After upgrading to Laravel 5.6.30 or later, verify that the vulnerability is no longer present using a vulnerability scanner or manual testing.
  • This guide is intended for informational purposes only and should not be considered a substitute for professional security advice.
  • It is important to consult with a qualified security professional to assess your specific risks and implement appropriate mitigation measures.