CVE-2024-4158 in Blocksy Plugin
Summary
by MITRE • 05/14/2024
The Blocksy theme for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘tagName’ parameter in versions up to, and including, 2.0.42 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 04/01/2025
The Blocksy WordPress theme presents a critical stored cross-site scripting vulnerability identified as CVE-2024-4158 affecting versions through 2.0.42. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the theme's codebase, specifically targeting the 'tagName' parameter. The flaw represents a significant security risk as it allows authenticated attackers who possess contributor-level permissions or higher to inject malicious scripts into theme elements that will execute whenever any user accesses the compromised pages. This vulnerability operates under the CWE-79 principle of cross-site scripting, where insufficient validation of user-supplied data creates opportunities for malicious code injection. The attack vector is particularly concerning because it leverages the trust relationship between the theme and its users, enabling persistent script execution that can compromise user sessions and data integrity.
The operational impact of this vulnerability extends beyond simple script injection as it enables attackers to perform a wide range of malicious activities including session hijacking, credential theft, and data exfiltration. When an authenticated user accesses a page containing the injected script, the malicious code executes within their browser context, potentially allowing attackers to escalate privileges or access sensitive information. The vulnerability affects the core functionality of the WordPress theme by compromising the integrity of content management systems where contributors and higher-level users have the ability to modify theme elements. This presents a particular risk in environments where multiple users have contributor access or higher permissions, as the attack can be initiated by any user with sufficient privileges to modify theme settings or content. The stored nature of this XSS vulnerability means that the malicious script persists in the database and executes every time the affected page is loaded, making it particularly dangerous for content management systems where multiple users interact with shared content.
Mitigation strategies for CVE-2024-4158 should prioritize immediate patching of the Blocksy theme to versions that address the input sanitization and output escaping deficiencies. Organizations should implement strict access controls and privilege management to limit the number of users with contributor-level permissions or higher, thereby reducing the attack surface. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular security audits of theme and plugin code should be conducted to identify similar vulnerabilities. Security monitoring should include detection of suspicious user activities and unauthorized modifications to theme elements. According to ATT&CK framework tactics, this vulnerability aligns with T1566 (Phishing) and T1059 (Command and Scripting Interpreter) as attackers can use the injected scripts to establish persistent access or execute commands on compromised systems. Organizations should also consider implementing web application firewalls to detect and block malicious script injection attempts, while maintaining regular updates to all WordPress components to ensure protection against known vulnerabilities. The vulnerability highlights the importance of proper input validation and output encoding practices in web applications, particularly in content management systems where user-generated content processing is common.