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The WordPress LiteSpeed Cache plugin, a popular tool with over five million active installations59, recently came under scrutiny due to a significant security vulnerability. This vulnerability tracked as CVE-2023-4000059, could potentially allow unauthenticated users to escalate their privileges on a WordPress site59.

Background of the Vulnerability

The LiteSpeed Cache plugin for WordPress is designed to improve site performance by storing a copy of website content for future requests9. This reduces the number of requests the server must process, thereby enhancing web page speed9.

However, a lack of input sanitisation and output escaping in the plugin’s code, combined with improper access control on one of its REST API endpoints, led to a significant vulnerability19. This vulnerability could potentially allow unauthorised access to sensitive information or privilege escalation on affected WordPress sites via a single HTTP request19.

Impact on WordPress Sites Running the Plugin

The vulnerability affects the LiteSpeed Cache plugin, which boasts over four million active installations1. It presents a risk of unauthenticated site-wide stored XSS (cross-site scripting). This could potentially allow unauthorised access to sensitive information or privilege escalation on affected WordPress sites via a single HTTP request1.

How Organisations Can Mitigate the Risk

To mitigate the risk, users are advised to update their LiteSpeed Cache plugin to the latest version112. As of the time of writing, the latest version is v6.112. Additionally, developers are encouraged to implement proper input sanitisation and output escaping in their code, particularly for data displayed in admin notices1.

The vendor has also implemented a permission check on the affected function to limit access to privileged users1. Despite the patch, the incident underscores the importance of proactive security measures in the development and maintenance of WordPress plugins, as vulnerabilities can have far-reaching consequences for website owners and users1.

General Preventative Advice on WordPress Maintenance

Keeping your WordPress plugins up-to-date is crucial for maintaining the security of your site12. If you have not updated in a while, it is strongly recommended to do so immediately12. Regularly monitoring security advisories and applying patches promptly can help protect your site from potential attacks.


The recent vulnerability in the WordPress LiteSpeed Cache plugin serves as a reminder of the importance of maintaining up-to-date security practices. By staying informed about potential vulnerabilities and taking prompt action to address them, website owners can help ensure the safety and integrity of their sites and importantly, their users’ data.


1 Infosecurity Magazine 5 Support 9 Qualys ThreatPROTECT 12 LiteSpeed Blog