The vulnerability identified as CVE-2025-13035 affects the Code Snippets plugin for WordPress, specifically all versions up to and including 3.9.1. The root cause is the use of PHP's extract() function on attacker-controlled shortcode attributes within the method evaluate_shortcode_from_flat_file. This function can overwrite the $filepath variable, which is later passed to require_once, enabling arbitrary PHP code execution on the server. The attack vector requires an authenticated user with at least Contributor-level privileges to craft a malicious shortcode using PHP filter chains. However, exploitation also depends on an administrator enabling the 'Enable file-based execution' setting and having at least one active content snippet, which creates a necessary condition for the code injection to succeed. This vulnerability falls under CWE-94 (Improper Control of Generation of Code), indicating a code injection flaw. The CVSS 3.1 base score is 8.0, with attack vector network (AV:N), high attack complexity (AC:H), low privileges required (PR:L), and user interaction required (UI:R). The scope is changed (S:C), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). Although no exploits are currently known in the wild, the vulnerability poses a significant risk due to the potential for remote code execution and full system compromise on affected WordPress installations.

For European organizations, this vulnerability presents a critical risk to WordPress-based websites that use the Code Snippets plugin. Successful exploitation can lead to arbitrary code execution, allowing attackers to compromise web servers, steal sensitive data, deface websites, or use the compromised server as a pivot point for further attacks within the network. Given the widespread use of WordPress across European businesses, including e-commerce, government, and media sectors, the impact could be severe. Confidentiality breaches could expose personal data protected under GDPR, leading to regulatory penalties. Integrity and availability impacts could disrupt business operations and damage organizational reputation. The requirement for authenticated access and admin interaction limits the attack surface but does not eliminate risk, especially in environments with multiple contributors or where social engineering could enable enabling the vulnerable setting.

European organizations should immediately audit their WordPress sites for the presence of the Code Snippets plugin and verify the version in use. The primary mitigation is to upgrade the plugin to a version that patches this vulnerability once available. Until a patch is released, administrators should disable the 'Enable file-based execution' setting to prevent exploitation. Additionally, organizations should enforce strict access controls, limiting Contributor-level privileges to trusted users only. Implement multi-factor authentication (MFA) for all WordPress accounts to reduce the risk of credential compromise. Regularly monitor logs for suspicious shortcode usage or unexpected file inclusions. Employ web application firewalls (WAFs) with rules to detect and block malicious PHP filter chains or unusual shortcode patterns. Conduct security awareness training to prevent social engineering attempts aimed at convincing administrators to enable risky settings. Finally, maintain regular backups and test restoration procedures to recover quickly in case of compromise.