CVE-2025-13847 identifies a stored Cross-Site Scripting (XSS) vulnerability in the PhotoFade plugin for WordPress, developed by davidangel. This vulnerability exists in all versions up to and including 0.2.1 and is due to improper neutralization of input during web page generation, specifically via the 'time' parameter. The root cause is insufficient input sanitization and lack of proper output escaping, which allows an attacker with authenticated Contributor-level access or higher to inject arbitrary JavaScript code into pages managed by the plugin. When other users access these pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the WordPress environment. The vulnerability does not require user interaction to trigger once the malicious script is stored and served, and it affects the confidentiality and integrity of user data. The CVSS v3.1 score of 6.4 reflects a medium severity, with an attack vector over the network, low attack complexity, and privileges required at the Contributor level. No patches are currently linked, and no known exploits are reported in the wild, but the vulnerability's presence in a popular CMS plugin makes it a significant risk. The vulnerability's scope is limited to WordPress sites using the PhotoFade plugin, but given WordPress's widespread use, the potential impact is broad. The CWE-79 classification confirms the nature of the vulnerability as a classic XSS issue.

For European organizations, this vulnerability poses a moderate risk primarily to websites and web applications running WordPress with the PhotoFade plugin installed. The ability for authenticated users with Contributor-level access to inject persistent scripts can lead to session hijacking, defacement, unauthorized content modification, or redirection to malicious sites. This can damage organizational reputation, lead to data breaches, and potentially facilitate further attacks such as privilege escalation or malware distribution. Organizations relying on WordPress for content management, especially those with multiple contributors or editors, are at higher risk. The impact on confidentiality and integrity is significant, though availability is not directly affected. Given the medium CVSS score and the requirement for authenticated access, the threat is less severe than unauthenticated remote code execution vulnerabilities but still requires timely remediation. European organizations in sectors such as media, e-commerce, education, and government that use WordPress extensively could face targeted exploitation attempts. Additionally, compliance with GDPR and other data protection regulations means that exploitation leading to data leakage could result in regulatory penalties.

1. Immediately audit WordPress sites to identify installations of the PhotoFade plugin and verify the version in use. 2. Restrict Contributor-level access strictly to trusted users, minimizing the number of users who can inject content. 3. Apply any available patches or updates from the plugin vendor as soon as they are released. In the absence of official patches, consider temporarily disabling or removing the PhotoFade plugin. 4. Implement Web Application Firewalls (WAFs) with rules designed to detect and block XSS payloads, especially those targeting the 'time' parameter or similar inputs. 5. Enforce strict input validation and output encoding on all user-supplied data within the WordPress environment, potentially via custom development or security plugins. 6. Monitor logs and user activity for unusual behavior indicative of exploitation attempts, such as unexpected script injections or anomalous page content changes. 7. Educate content contributors about the risks of XSS and safe content management practices. 8. Conduct regular security assessments and penetration testing focused on WordPress plugins and user input handling. 9. Consider implementing Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. 10. Maintain backups and incident response plans to quickly recover from any successful exploitation.