CVE-2025-66093 identifies a DOM-based Cross-site Scripting (XSS) vulnerability in the hupe13 Extensions for Leaflet Map, a popular JavaScript library extension used to enhance interactive web maps. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, which allows malicious actors to inject and execute arbitrary scripts within the victim's browser context. This can occur when the extension processes input parameters or data without adequate sanitization or encoding, leading to script execution in the Document Object Model (DOM). The affected versions include all releases up to and including version 4.8. The CVSS 3.1 base score is 6.5, indicating a medium severity level. The vector string (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L) reveals that the attack can be performed remotely over the network with low attack complexity, requires low privileges, and user interaction is necessary. The scope is changed, meaning the vulnerability affects resources beyond the initially vulnerable component. The impact includes partial loss of confidentiality, integrity, and availability, such as session hijacking, unauthorized actions, or defacement of web content. No public exploits are currently known, but the vulnerability poses a risk to any web application integrating the hupe13 Leaflet Map extensions, especially those exposing user input in map-related interfaces. The vulnerability was published on November 21, 2025, and no official patches or mitigations have been linked yet. The vulnerability is tracked by Patchstack and the CVE database.

For European organizations, the impact of CVE-2025-66093 can be significant, especially for entities relying on web-based geographic information systems (GIS), mapping services, or location-based applications that utilize the hupe13 Extensions for Leaflet Map. Successful exploitation could allow attackers to execute malicious scripts in users' browsers, leading to session hijacking, theft of sensitive data such as authentication tokens or personal information, unauthorized actions performed on behalf of users, or defacement of web content. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR breaches), and cause operational disruptions. Since the vulnerability requires user interaction and low privileges, phishing or social engineering campaigns could be used to trigger exploitation. The partial compromise of confidentiality, integrity, and availability may affect customer trust and lead to financial losses. Additionally, organizations in sectors such as government, transportation, utilities, and environmental monitoring, which often use mapping technologies, may face higher risks. The absence of known exploits reduces immediate threat but does not eliminate future risk, emphasizing the need for proactive mitigation.

1. Monitor for and apply official patches or updates from the hupe13 project as soon as they become available to address this vulnerability. 2. Implement strict input validation and output encoding on all user-supplied data before it is processed or rendered by the Leaflet Map extensions to prevent injection of malicious scripts. 3. Employ Content Security Policy (CSP) headers to restrict the execution of untrusted scripts and reduce the impact of potential XSS attacks. 4. Conduct thorough code reviews and security testing focusing on client-side input handling within web applications using the affected extensions. 5. Educate users and administrators about the risks of phishing and social engineering that could facilitate exploitation requiring user interaction. 6. Where feasible, isolate or sandbox map components to limit the scope of script execution. 7. Use web application firewalls (WAFs) with rules tailored to detect and block suspicious input patterns related to XSS. 8. Regularly audit and update third-party libraries and dependencies to minimize exposure to known vulnerabilities.