CVE-2025-52771 is a Stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the bcupham Video Expander product up to version 1.0. Stored XSS occurs when malicious input is improperly neutralized and subsequently stored by the web application, later being served to users without adequate sanitization or encoding. This vulnerability allows an attacker with at least low privileges (PR:L) and requiring user interaction (UI:R) to inject malicious scripts into web pages generated by the Video Expander application. The vulnerability is remotely exploitable over the network (AV:N) with low attack complexity (AC:L). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component, potentially impacting other parts of the application or user sessions. The CVSS v3.1 base score is 6.5, categorized as medium severity, reflecting limited but notable impacts on confidentiality, integrity, and availability. Specifically, the vulnerability can lead to partial disclosure of information (C:L), modification of data or application state (I:L), and some disruption of service (A:L). No patches or known exploits in the wild have been reported as of the publication date (August 14, 2025). The vulnerability arises from improper input neutralization during web page generation, meaning that user-supplied data is not correctly sanitized or encoded before being embedded in HTML output, enabling script injection that executes in the context of other users' browsers.

For European organizations using bcupham Video Expander, this vulnerability poses a risk of client-side script injection that can lead to session hijacking, credential theft, or unauthorized actions performed on behalf of users. The stored nature of the XSS means that malicious scripts persist and can affect multiple users over time, increasing the attack surface. Confidentiality is at risk due to potential exposure of sensitive user data or internal application information. Integrity may be compromised if attackers manipulate displayed content or application behavior. Availability impact is generally limited but could include denial-of-service conditions if scripts disrupt normal application functionality. Organizations in sectors with high regulatory requirements for data protection, such as finance, healthcare, and government, could face compliance issues if user data is exposed or manipulated. Additionally, reputational damage and loss of user trust are significant concerns. Since exploitation requires some level of user privileges and interaction, insider threats or compromised user accounts could facilitate attacks. The absence of known exploits in the wild suggests limited immediate risk, but proactive mitigation is advisable to prevent future exploitation.

To mitigate CVE-2025-52771, European organizations should implement a multi-layered approach: 1) Apply input validation and output encoding rigorously—ensure all user-supplied data is sanitized and properly encoded before inclusion in HTML pages, using context-aware encoding libraries. 2) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 3) Enforce strict access controls and least privilege principles to limit the ability of users to inject malicious content. 4) Monitor and audit application logs for unusual input patterns or script injection attempts. 5) Since no official patch is currently available, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block XSS payloads targeting Video Expander. 6) Educate users about phishing and social engineering risks to reduce successful exploitation via user interaction. 7) Engage with the vendor or community for updates or patches and plan for timely application once available. 8) Conduct regular security assessments and penetration testing focusing on input handling and stored XSS vectors within the application environment.