CVE-2025-8878 is a medium-severity vulnerability classified under CWE-94 (Improper Control of Generation of Code, also known as Code Injection) affecting the WordPress plugin 'Paid Membership Plugin, Ecommerce, User Registration Form, Login Form, User Profile & Restrict Content – ProfilePress' developed by properfraction. This vulnerability exists in all versions up to and including 4.16.4. The root cause is the plugin's failure to properly validate user-supplied input before executing the WordPress function do_shortcode. This function processes shortcodes, which are snippets of code embedded in WordPress content to dynamically generate content or functionality. Because the plugin does not restrict or sanitize the input passed to do_shortcode, an unauthenticated attacker can inject arbitrary shortcodes and have them executed on the server. This can lead to unauthorized code execution within the context of the WordPress site. The CVSS v3.1 base score is 6.5, reflecting a medium severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and limited impact on confidentiality and integrity (C:L/I:L) but no impact on availability (A:N). Although no known exploits are currently reported in the wild, the vulnerability's nature allows remote, unauthenticated exploitation, making it a significant risk for affected sites. The lack of patch links suggests that at the time of this report, no official fix has been released yet. Given the plugin's wide functionality covering membership, ecommerce, user registration, login, profile management, and content restriction, exploitation could allow attackers to manipulate site content, escalate privileges, or potentially pivot to further attacks within the hosting environment.

For European organizations using WordPress sites with this plugin, the vulnerability poses a risk of unauthorized code execution without authentication. This could lead to data leakage, unauthorized content manipulation, or compromise of user accounts, especially in ecommerce or membership contexts where sensitive personal and payment data may be processed. The integrity of user profiles and restricted content could be undermined, damaging trust and potentially violating GDPR requirements for data protection. Additionally, attackers could leverage this vulnerability to implant malicious code, conduct phishing campaigns, or use the compromised site as a launchpad for attacks on visitors or internal networks. The medium severity score indicates a moderate but tangible risk, particularly for organizations relying heavily on this plugin for critical business functions. The absence of required user interaction and privileges lowers the barrier for exploitation, increasing the threat level. The impact on availability is minimal, but the confidentiality and integrity impacts could have regulatory and reputational consequences for European entities.

Immediate mitigation steps include: 1) Temporarily disabling or removing the affected plugin until a patch is available. 2) Restricting access to the WordPress admin and user-facing forms associated with the plugin via IP whitelisting or web application firewall (WAF) rules to block suspicious shortcode injection attempts. 3) Monitoring web server and WordPress logs for unusual shortcode execution patterns or unexpected content changes. 4) Applying strict input validation and sanitization on all user inputs related to shortcode processing, if custom modifications are possible. 5) Keeping WordPress core and all plugins updated and subscribing to vendor security advisories for prompt patch deployment once available. 6) Employing security plugins that can detect and block malicious shortcode execution or code injection attempts. 7) Conducting regular security audits and penetration testing focusing on plugin vulnerabilities. These measures go beyond generic advice by focusing on access control, monitoring, and proactive detection tailored to shortcode injection risks.