CVE-2025-28960 is a high-severity reflected Cross-Site Scripting (XSS) vulnerability identified in the web application "Evangelische Termine" developed by regibaer. This vulnerability arises due to improper neutralization of user-supplied input during web page generation, classified under CWE-79. Specifically, the application fails to adequately sanitize or encode input parameters before reflecting them back in HTTP responses, enabling attackers to inject malicious scripts. The vulnerability affects all versions up to 3.3, with no specific version exclusions noted. The CVSS 3.1 base score is 7.1, indicating a high impact with the vector string AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L, meaning the attack can be launched remotely over the network with low attack complexity, requires no privileges but does require user interaction, and results in a scope change affecting confidentiality, integrity, and availability to a limited extent. Reflected XSS can be exploited by tricking users into clicking crafted URLs or submitting malicious input that executes arbitrary JavaScript in their browsers. This can lead to session hijacking, credential theft, defacement, or redirection to malicious sites. Although no known exploits are currently reported in the wild, the vulnerability's characteristics make it a credible threat if weaponized. Evangelische Termine is a scheduling or event management platform likely used by religious or community organizations, which may involve sensitive user data and trusted user bases. The lack of available patches at the time of publication suggests that affected organizations should prioritize mitigation and monitoring efforts.

For European organizations, particularly those using Evangelische Termine for managing community or religious event schedules, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to user sessions, leakage of personal or organizational data, and potential defacement or manipulation of event information. Given the nature of the platform, trust relationships within communities could be undermined, and attackers might leverage the platform to distribute malware or phishing content to users. The reflected XSS could also be used as a vector for broader attacks targeting users' browsers or internal networks if combined with other vulnerabilities. The scope change indicated by the CVSS vector suggests that the vulnerability could impact multiple users or systems beyond the initially targeted user. European organizations are subject to strict data protection regulations such as GDPR; thus, exploitation resulting in data breaches could lead to regulatory penalties and reputational damage. The requirement for user interaction means social engineering or phishing campaigns could be used to trigger the exploit, increasing the risk in environments with less cybersecurity awareness.

To mitigate CVE-2025-28960, organizations should implement a multi-layered approach beyond generic advice: 1) Immediate input validation and output encoding: Developers must ensure that all user-supplied inputs reflected in web pages are properly sanitized using context-appropriate encoding (e.g., HTML entity encoding for HTML contexts, JavaScript escaping for inline scripts). 2) Content Security Policy (CSP): Deploy a strict CSP header to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 3) User awareness training: Educate users about the risks of clicking on suspicious links or submitting untrusted inputs, as user interaction is required for exploitation. 4) Web Application Firewall (WAF): Configure WAF rules to detect and block common XSS attack patterns targeting the Evangelische Termine application. 5) Monitoring and logging: Enable detailed logging of web requests and monitor for unusual input patterns or error messages that could indicate attempted exploitation. 6) Patch management: Engage with the vendor regibaer to obtain or request patches or updates addressing this vulnerability as soon as they become available. 7) Isolate the application environment: Run the application with least privilege and segregate it from critical internal systems to limit potential lateral movement in case of compromise.