CVE-2025-11863 is a stored Cross-Site Scripting (XSS) vulnerability identified in the My Geo Posts Free plugin for WordPress, which is widely used to display geolocation-based posts. The vulnerability stems from the plugin's failure to properly sanitize or escape the 'default' attribute of the 'mygeo_city' shortcode, allowing authenticated users with contributor-level or higher privileges to inject arbitrary JavaScript code into pages. This malicious code is stored persistently and executed in the browsers of any users who visit the affected pages, potentially leading to session hijacking, data theft, or unauthorized actions performed on behalf of the victim. The vulnerability does not require user interaction beyond visiting the compromised page and has a CVSS 3.1 base score of 6.4, reflecting medium severity. The attack vector is network-based with low attack complexity, requiring only authenticated contributor access, which is a relatively low privilege level in WordPress. The scope is changed (S:C) because the vulnerability affects not only the plugin but can impact the confidentiality and integrity of user data across the WordPress site. No official patches or fixes have been released at the time of publication, and no known exploits have been observed in the wild. The vulnerability is categorized under CWE-79, which involves improper neutralization of input during web page generation, a common vector for XSS attacks. This vulnerability highlights the risks posed by insufficient input validation in widely deployed CMS plugins, especially those that allow user-generated content to be embedded dynamically.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of their WordPress-based websites. Attackers with contributor-level access can inject malicious scripts that execute in the browsers of site visitors, potentially leading to session hijacking, credential theft, defacement, or redirection to malicious sites. This can damage organizational reputation, lead to data breaches involving personal data protected under GDPR, and cause operational disruptions. Since WordPress is widely used across Europe, especially by SMEs and public sector entities, the attack surface is substantial. The vulnerability could also be leveraged as a foothold for further attacks within the network if attackers escalate privileges or steal administrative credentials. The lack of user interaction required for exploitation increases the risk, as any visitor to the compromised page may be affected. Additionally, the persistent nature of stored XSS means the malicious payload remains active until removed, increasing exposure time. Organizations in sectors with high regulatory scrutiny, such as finance, healthcare, and government, face heightened compliance risks if exploited.

1. Immediately audit and restrict contributor-level access to trusted users only, minimizing the number of accounts that can exploit this vulnerability. 2. Implement Web Application Firewall (WAF) rules that detect and block suspicious script injections in shortcode attributes, focusing on the 'mygeo_city' shortcode. 3. Use security plugins that provide XSS protection and content sanitization for WordPress sites. 4. Manually sanitize and validate all user inputs related to the 'mygeo_city' shortcode by applying custom filters or hooks in WordPress to escape output properly until an official patch is released. 5. Monitor website content for unexpected script tags or injected code, especially in pages using the vulnerable shortcode. 6. Educate content contributors about the risks of injecting untrusted content and enforce strict content policies. 7. Regularly back up website data to enable quick restoration if an attack occurs. 8. Stay alert for official patches or updates from the plugin vendor and apply them promptly once available. 9. Consider temporarily disabling the My Geo Posts Free plugin if the risk outweighs the benefit until a fix is released.