CVE-2025-50015 is a Stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, affecting the Rodrigo Bastos Hand Talk software up to version 6.0. Stored XSS occurs when malicious input is improperly neutralized and then persistently stored by the application, later being served to users without adequate sanitization. This vulnerability allows an attacker with high privileges (as indicated by the CVSS vector requiring PR:H) and user interaction to inject malicious scripts into web pages generated by Hand Talk. When other users access these pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The CVSS 3.1 base score is 5.9 (medium severity), reflecting that the attack vector is network-based (AV:N), with low attack complexity (AC:L), but requiring high privileges and user interaction (UI:R). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The impact on confidentiality, integrity, and availability is low to moderate (C:L/I:L/A:L), meaning some data exposure or modification is possible, but not complete system compromise. No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability affects all versions up to 6.0, but the exact earliest affected version is unspecified (n/a). The vulnerability arises from improper input neutralization during web page generation, a common cause of XSS flaws, emphasizing the need for robust input validation and output encoding in the affected software.

For European organizations using Rodrigo Bastos Hand Talk, this vulnerability poses a moderate risk primarily to web application security and user data confidentiality. Since Hand Talk is a communication tool (likely related to sign language or accessibility), organizations in education, government, healthcare, and public services that rely on it for communication accessibility may be targeted. Exploitation could lead to session hijacking or unauthorized actions within the application, potentially exposing sensitive user data or disrupting communication services. The requirement for high privileges to exploit reduces the risk from external attackers but raises concern about insider threats or compromised accounts. The changed scope means that the impact could extend beyond the immediate application, possibly affecting integrated systems or user environments. Although no active exploits are known, the medium severity and the nature of stored XSS vulnerabilities mean that once exploited, the impact on user trust and compliance with data protection regulations (such as GDPR) could be significant, especially if personal data is exposed or manipulated.

1. Implement strict input validation and output encoding: Developers should ensure that all user-supplied input is properly sanitized and encoded before being stored or rendered in web pages, using context-appropriate escaping techniques (e.g., HTML entity encoding). 2. Apply Content Security Policy (CSP): Deploy a robust CSP header to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 3. Enforce least privilege principles: Limit user privileges within Hand Talk to reduce the risk of high-privilege account compromise. 4. Monitor and audit user inputs and application logs for suspicious activities that might indicate attempted exploitation. 5. Educate users about phishing and social engineering risks, since user interaction is required for exploitation. 6. Since no patch is currently available, consider temporary mitigations such as disabling or restricting features that accept user-generated content or isolating the application environment. 7. Plan for timely patch deployment once an official fix is released by the vendor. 8. Conduct regular security assessments and penetration testing focusing on XSS vulnerabilities in Hand Talk deployments.