WordPress sites impacted by the WP Fastest Cache plugin flaw

February 12, 2024
WordPress Website Protection Plugin WP Fastest Cache Security Flaw Vulnerability

The popular WordPress plugin WP Fastest Cache has exposed over 600,000 websites to cyberattacks after having a critical SQL injection flaw. Investigations revealed that the flaw is CVE-2023-6063, which has a critical severity score of 8.6 out of 10. Moreover, the vulnerability has prompted urgent warnings from cybersecurity experts.

WP Fastest Cache, known for enhancing page load speeds, improving visitor experience, and optimising Google search rankings, is a widely used caching plugin that gathered over a million installations. However, recent download statistics reveal that thousands of users are still operating plugin versions prone to the earlier-mentioned security vulnerability.


The WP Fastest Cache vulnerability affects all versions aside from the recently released.


WP Fastest Cache admins revealed that the SQL injection vulnerability impacts all plugin versions except the recently released patch, version 1.2.2.

SQL injection vulnerabilities, like the one found in WP Fastest Cache, appear when the software fails to properly validate user input, enabling hackers to manipulate SQL queries and potentially acquire unauthorised access to a site’s database.

The specific vulnerability resides in the ‘is_user_admin’ function of the ‘WpFastestCacheCreateCache’ class within the plugin. Exploiting this flaw involves controlling the ‘username’ value extracted from cookies.

In addition, since the ‘username’ input lacks proper sanitisation, attackers can manipulate the cookie value by modifying the plugin’s SQL query and obtaining unauthorised access to sensitive information stored in the WordPress database.

WordPress databases typically hold various types of data, such as sensitive information, including user data like IP addresses, emails, IDs, account passwords, and crucial configuration settings for plugins and themes. The potential exposure of such critical data shows how severe the impact that this vulnerability can inflict on vulnerable websites.

Fortunately, the developers of WP Fastest Cache have responded immediately to the discovery of the vulnerability, releasing a fix in patch 1.2.2. However, plugin users should immediately adopt the new version to mitigate the risk of falling victim to potential attacks.

Experts believe that threat actors could have exploited the flaws already. Therefore, plugin users should be vigilant with their websites and be wary of unwanted activities.

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