CVE-2025-5488 is a Stored Cross-Site Scripting (XSS) vulnerability identified in the WP Masonry & Infinite Scroll WordPress plugin developed by kaushik07. This vulnerability affects all versions up to and including 2.2 of the plugin. The root cause is insufficient input sanitization and output escaping of user-supplied attributes within the plugin's 'wmis' shortcode. Specifically, authenticated users with contributor-level privileges or higher can inject arbitrary JavaScript code into pages via the shortcode parameters. When other users visit these compromised pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions performed on behalf of the victim. The vulnerability does not require user interaction beyond visiting the infected page, and no higher authentication level than contributor is necessary to exploit it. The CVSS v3.1 base score is 6.4, reflecting a medium severity level, with an attack vector of network, low attack complexity, and privileges required at the contributor level. The scope is changed, indicating that the vulnerability affects components beyond the initially vulnerable plugin, potentially impacting the broader WordPress environment. No known public exploits or patches are currently available, and the vulnerability was published on June 26, 2025. This vulnerability falls under CWE-79, which is a common and well-understood class of web application security flaws related to improper neutralization of input during web page generation.

For European organizations using WordPress websites with the WP Masonry & Infinite Scroll plugin, this vulnerability poses a significant risk to confidentiality and integrity. Attackers with contributor access can inject malicious scripts that execute in the browsers of site visitors, including administrators or other privileged users, potentially leading to session hijacking, theft of sensitive data, unauthorized content modification, or distribution of malware. This can damage organizational reputation, lead to data breaches, and cause regulatory compliance issues under GDPR due to exposure of personal data. The vulnerability does not directly affect availability but can indirectly cause service disruptions if exploited to deface websites or inject malicious payloads that trigger security mechanisms or user distrust. Since contributor-level access is required, the threat is more relevant in environments where multiple users have content creation privileges, such as media companies, educational institutions, and e-commerce platforms. The scope change in the CVSS vector suggests that the impact could extend beyond the plugin itself, potentially affecting other integrated components or plugins, increasing the risk profile. Given the widespread use of WordPress in Europe and the popularity of plugins enhancing site functionality, this vulnerability could be leveraged in targeted attacks against organizations with valuable web assets or high visitor traffic.

1. Immediate mitigation involves restricting contributor-level access to trusted users only and reviewing existing user roles to minimize unnecessary privileges. 2. Disable or remove the WP Masonry & Infinite Scroll plugin until a security patch or update is released by the vendor. 3. Implement Web Application Firewall (WAF) rules to detect and block malicious payloads targeting the 'wmis' shortcode parameters. 4. Conduct a thorough audit of all user-generated content and shortcode usage to identify and remove any injected scripts. 5. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts on affected websites. 6. Monitor website logs for unusual activity or repeated shortcode usage patterns indicative of exploitation attempts. 7. Educate content contributors about the risks of injecting untrusted input and enforce strict input validation policies at the application level. 8. Once available, promptly apply official patches or updates from the plugin vendor. 9. Consider isolating or sandboxing content created by contributors to limit the impact of potential XSS payloads. These steps go beyond generic advice by focusing on access control, proactive detection, and layered defenses tailored to the specific vulnerability vector.