CVE-2025-11289 is a cross-site scripting (XSS) vulnerability identified in the westboy CicadasCMS product, specifically affecting versions up to commit 2431154dac8d0735e04f1fd2a3c3556668fc8dab. The vulnerability resides in the Save function within the TemplateFileServiceImpl.java file, part of the Template Management Page component. This function improperly handles user input, allowing an attacker to inject malicious scripts that are then executed in the context of the victim's browser. The vulnerability can be exploited remotely without requiring authentication, but user interaction is necessary for the malicious script to execute, such as by tricking a user into visiting a crafted URL or interacting with a manipulated page. The CVSS 4.0 base score is 4.8 (medium severity), reflecting the network attack vector, low attack complexity, no privileges required, but requiring user interaction. The impact primarily affects confidentiality and integrity at a limited scope, with no direct impact on availability or system control. Although no public exploits have been observed in the wild, the vulnerability has been publicly disclosed, increasing the risk of exploitation. The lack of available patches or mitigations from the vendor at the time of disclosure further elevates the urgency for organizations to implement compensating controls. Given that CicadasCMS is a content management system, exploitation could lead to session hijacking, defacement, or redirection to malicious sites, potentially impacting website visitors and administrators.

For European organizations using westboy CicadasCMS, this vulnerability poses a moderate risk. Successful exploitation could allow attackers to execute arbitrary scripts in the browsers of users interacting with the CMS, potentially leading to credential theft, session hijacking, or delivery of malware. This can damage organizational reputation, lead to data breaches, and cause regulatory compliance issues under GDPR due to unauthorized access to personal data. Since the vulnerability affects the template management functionality, attackers might also manipulate website content, causing misinformation or defacement. Organizations relying on CicadasCMS for public-facing websites or internal portals may experience trust erosion and operational disruptions. The medium severity score suggests the impact is not critical but still significant, especially for sectors with high compliance requirements or sensitive user bases.

1. Immediate mitigation should include disabling or restricting access to the Template Management Page, especially the Save function, to trusted administrators only. 2. Implement strict input validation and output encoding on all user-supplied data within the CMS templates to prevent script injection. 3. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 4. Monitor web server logs and CMS activity for unusual requests or patterns indicative of exploitation attempts. 5. Educate users and administrators about the risks of clicking untrusted links or interacting with suspicious content. 6. If possible, isolate the CMS environment from critical internal networks to limit lateral movement in case of compromise. 7. Engage with the vendor or community to obtain patches or updates addressing this vulnerability as soon as they become available. 8. Consider deploying web application firewalls (WAFs) with custom rules to detect and block XSS payloads targeting the vulnerable endpoint.