CVE-2024-13557 identifies a code injection vulnerability in the Shortcodes by United Themes WordPress plugin, versions up to and including 5.1.6. The vulnerability arises because the plugin improperly controls the generation of code by failing to validate user-supplied input before passing it to the do_shortcode function. This function executes WordPress shortcodes, which can embed dynamic content or code. An unauthenticated attacker can exploit this flaw by sending crafted requests that trigger arbitrary shortcode execution, potentially allowing them to manipulate site content or execute malicious code within the context of the WordPress site. The vulnerability is classified under CWE-94, indicating improper control of code generation. The CVSS 3.1 base score is 6.5 (medium), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and limited confidentiality and integrity impacts without affecting availability. No known exploits have been reported in the wild as of the publication date. The vulnerability affects all versions of the plugin up to 5.1.6, which is widely used in WordPress sites for shortcode management. The lack of input validation and authentication requirements makes this vulnerability a significant risk for websites using this plugin, especially those exposed to the internet without additional protective controls.

The primary impact of CVE-2024-13557 is the potential unauthorized execution of arbitrary shortcodes on vulnerable WordPress sites. This can lead to limited confidentiality breaches, such as unauthorized disclosure of sensitive information embedded in shortcode outputs, and integrity issues, including unauthorized content modification or injection of malicious scripts. Although the vulnerability does not directly affect availability, the integrity compromise could facilitate further attacks like cross-site scripting (XSS) or privilege escalation if combined with other vulnerabilities. Organizations running affected versions of the plugin face risks of website defacement, data leakage, or use of their sites as a vector for broader attacks against visitors or connected systems. The ease of exploitation without authentication increases the threat level, especially for publicly accessible WordPress sites. The absence of known exploits in the wild reduces immediate risk but does not eliminate the potential for future attacks, particularly as exploit code could be developed and shared. The impact is more pronounced for organizations relying heavily on WordPress for their web presence, including small to medium enterprises, content publishers, and e-commerce platforms.

To mitigate CVE-2024-13557, organizations should first check for and apply any official patches or updates released by United Themes addressing this vulnerability. If no patch is currently available, administrators should consider temporarily disabling the Shortcodes by United Themes plugin or restricting access to the affected shortcode execution endpoints via web application firewalls (WAFs) or server-level access controls. Implementing strict input validation and sanitization on all user-supplied data that interacts with shortcode processing can reduce exploitation risk. Monitoring web server logs for unusual or suspicious requests targeting shortcode functionality can help detect attempted exploitation. Additionally, employing security plugins that limit shortcode execution or restrict shortcode usage to trusted users can provide an extra layer of defense. Regularly auditing installed plugins for vulnerabilities and maintaining a robust WordPress security posture, including least privilege principles and timely updates, will help mitigate similar risks. Organizations should also educate site administrators about the risks of installing untrusted plugins and encourage the use of security best practices for WordPress deployments.