CVE-2025-3750 is a medium-severity vulnerability classified as CWE-79, indicating an improper neutralization of input during web page generation, commonly known as Cross-Site Scripting (XSS). This vulnerability affects the Network Posts Extended plugin for WordPress, developed by johnzenausa, in all versions up to and including 7.7.1. The root cause is insufficient input sanitization and output escaping of the 'post_height' parameter. An authenticated attacker with Contributor-level access or higher can exploit this flaw by injecting arbitrary JavaScript code into pages generated by the plugin. Because the vulnerability is stored XSS, the malicious script persists in the application and executes whenever any user accesses the compromised page. The CVSS v3.1 base score is 6.4, reflecting a medium severity with the vector AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N. This means the attack can be launched remotely over the network with low attack complexity, requires privileges equivalent to a Contributor role, does not require user interaction, and impacts confidentiality and integrity with a scope change (the vulnerability affects resources beyond the attacker’s privileges). Stored XSS can lead to session hijacking, defacement, phishing, or unauthorized actions performed on behalf of users. While no known exploits are currently reported in the wild, the vulnerability poses a significant risk to WordPress sites using this plugin, especially those with multiple contributors and visitors.

For European organizations, this vulnerability can have several impacts. Many European companies and institutions rely on WordPress for their websites and content management, often using plugins like Network Posts Extended to enhance functionality. An attacker exploiting this vulnerability could inject malicious scripts that steal user credentials, perform unauthorized actions, or spread malware to visitors, potentially damaging reputation and trust. Confidentiality is impacted as attackers can access sensitive session tokens or personal data. Integrity is compromised since injected scripts can alter displayed content or manipulate user interactions. Although availability is not directly affected, the resulting phishing or malware distribution could lead to indirect service disruptions. Organizations in regulated sectors such as finance, healthcare, and government in Europe must be particularly cautious due to strict data protection laws like GDPR, which mandate safeguarding user data and reporting breaches. Failure to address this vulnerability could result in legal penalties and loss of customer confidence.

Specific mitigation steps include: 1) Immediate update or patching of the Network Posts Extended plugin once a fix is released by the vendor. Since no patch links are currently available, organizations should monitor official sources closely. 2) As a temporary measure, restrict Contributor-level and higher permissions to trusted users only, minimizing the risk of malicious input. 3) Implement Web Application Firewall (WAF) rules tailored to detect and block suspicious payloads targeting the 'post_height' parameter. 4) Employ Content Security Policy (CSP) headers to restrict execution of unauthorized scripts on affected pages. 5) Conduct thorough code reviews and input validation enhancements for custom or third-party plugins to ensure proper sanitization and escaping. 6) Educate content contributors about the risks of injecting untrusted content and enforce strict content moderation policies. 7) Regularly scan WordPress sites with security tools to detect stored XSS and other vulnerabilities. 8) Backup website data frequently to enable recovery in case of compromise.