CVE-2025-50053 identifies a reflected Cross-site Scripting (XSS) vulnerability classified under CWE-79 in the nebelhorn Blappsta Mobile App Plugin, which supports native iPhone and Android applications. The vulnerability stems from improper neutralization of input during the generation of web pages within the app, allowing attackers to inject malicious JavaScript code that is reflected back to users. This reflected XSS can be exploited remotely without requiring authentication, but it necessitates user interaction, such as clicking a maliciously crafted URL. The CVSS v3.1 score of 7.1 reflects its high severity, with attack vector being network-based, low attack complexity, no privileges required, but user interaction needed. The vulnerability impacts confidentiality by potentially exposing sensitive user data, integrity by enabling script injection that can alter app behavior, and availability by causing app crashes or denial of service. The scope is changed (S:C), indicating that exploitation can affect components beyond the vulnerable plugin, possibly compromising the entire app environment. Currently, no patches or fixes have been published, and no known exploits have been observed in the wild, but the risk remains significant due to the ease of exploitation and potential impact. The vulnerability affects all versions up to 0.8.8.8, with no specific version exclusions noted. The plugin is used in mobile apps, which are widely deployed, increasing the attack surface. The reflected XSS nature means attackers can craft URLs or inputs that, when processed by the app, execute malicious scripts in the context of the victim's session, leading to session hijacking, credential theft, or unauthorized actions within the app.

For European organizations, this vulnerability poses a significant risk especially for those deploying mobile applications using the Blappsta Mobile App Plugin. The reflected XSS can lead to unauthorized access to user sessions, data leakage, and manipulation of app content, undermining user trust and potentially violating GDPR requirements concerning data protection. Financial institutions, healthcare providers, and e-commerce platforms in Europe are particularly vulnerable due to the sensitive nature of their data and regulatory scrutiny. The vulnerability could be exploited to deliver phishing attacks or malware via the app, impacting availability and causing reputational damage. Since mobile apps are widely used across Europe, the attack surface is broad, and the impact could extend to millions of users. Additionally, the cross-origin nature of mobile app webviews may exacerbate the impact by allowing attackers to bypass same-origin policies. The lack of available patches increases the urgency for organizations to implement compensating controls. Failure to address this vulnerability could result in regulatory penalties and loss of customer confidence.

1. Implement strict input validation and sanitization on all user-supplied data before it is processed or reflected in the app's web views. 2. Apply proper output encoding (e.g., HTML entity encoding) to neutralize any potentially malicious scripts before rendering. 3. Deploy Content Security Policy (CSP) headers within the app's web views to restrict the execution of unauthorized scripts. 4. Monitor and restrict the use of dynamic content generation within the app to minimize injection points. 5. Educate users to avoid clicking on suspicious links or interacting with untrusted content within the app. 6. Conduct regular security assessments and penetration testing focused on mobile app webviews and plugins. 7. Engage with the vendor (nebelhorn) to obtain patches or updates as soon as they become available. 8. Consider implementing runtime application self-protection (RASP) mechanisms to detect and block XSS attempts in real-time. 9. Use mobile app security frameworks that provide built-in XSS protections. 10. Isolate sensitive app functions from webview components to limit the impact of any script execution.