CVE-2024-5595 in Essential Blocks Plugin
Summary
by MITRE • 08/02/2024
The Essential Blocks WordPress plugin before 4.7.0 does not validate and escape some of its block options before outputting them back in a page/post where the block is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks
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Analysis
by VulDB Data Team • 03/16/2025
The Essential Blocks WordPress plugin vulnerability CVE-2024-5595 represents a critical stored cross-site scripting flaw that affects versions prior to 4.7.0. This vulnerability exists within the plugin's handling of block options where insufficient validation and escaping mechanisms are implemented during the output process. The flaw specifically targets the plugin's block rendering functionality, creating a pathway for malicious actors to inject persistent scripts into WordPress pages and posts where these blocks are embedded.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user input within its block options system. When contributors and higher-privileged users create or modify content using Essential Blocks, the plugin processes these inputs without adequate validation checks. This inadequate input sanitization allows malicious scripts to be stored within the WordPress database and subsequently executed whenever the affected page or post is rendered. The vulnerability specifically affects users with the contributor role and above, which includes authors, editors, and administrators, making it particularly dangerous in multi-user environments where less privileged users might have access to block editing functionality.
From an operational impact perspective, this vulnerability enables attackers to perform persistent XSS attacks that can compromise user sessions, steal sensitive information, or redirect users to malicious websites. The stored nature of the vulnerability means that once malicious scripts are injected, they persist indefinitely until manually removed or the plugin is updated. This creates a significant risk for WordPress sites that rely heavily on user-generated content or have multiple contributors with varying privilege levels. The vulnerability can be exploited to execute malicious code in the context of the victim's browser, potentially leading to complete account compromise or data exfiltration.
The vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws, and demonstrates characteristics consistent with ATT&CK technique T1566.001 for initial access through malicious content. Organizations using Essential Blocks should immediately implement the recommended mitigation of updating to version 4.7.0 or later, which includes proper input validation and output escaping mechanisms. Additional defensive measures include restricting user privileges where possible, implementing content security policies, and monitoring for suspicious block modifications. The vulnerability highlights the importance of input validation in web applications and underscores the need for proper sanitization of user-provided data before it is stored and rendered back to users, particularly in content management systems where multiple user roles interact with editable components.