CVE-2025-48105 is a Stored Cross-site Scripting (XSS) vulnerability identified in the Vincent Boiardt Easy Flash Embed plugin, affecting versions up to 1.0. The vulnerability arises due to improper neutralization of input during web page generation, classified under CWE-79. This flaw allows an attacker with at least some level of privileges (PR:L) and requiring user interaction (UI:R) to inject malicious scripts that are stored persistently within the application. When other users or administrators access the affected pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, defacement, or redirection to malicious sites. The CVSS 3.1 base score is 6.5 (medium severity), with an attack vector of network (AV:N), low attack complexity (AC:L), privileges required (PR:L), user interaction required (UI:R), and a scope change (S:C) indicating that the vulnerability affects components beyond the initially vulnerable component. The impact affects confidentiality, integrity, and availability to a limited extent (C:L/I:L/A:L). No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability is significant because Easy Flash Embed is used to embed Flash content in websites, often in content management systems or personal/business websites, which may be targeted by attackers to leverage stored XSS for broader attacks such as phishing or lateral movement within networks.

For European organizations, this vulnerability poses a moderate risk, especially for those using the Easy Flash Embed plugin on public-facing websites. Stored XSS can lead to theft of user credentials, session tokens, or other sensitive information, undermining user trust and potentially violating GDPR requirements related to data protection and breach notification. The scope change in the CVSS vector suggests that exploitation could impact components beyond the plugin itself, possibly affecting the entire web application or connected systems. Organizations in sectors with high web presence such as e-commerce, media, education, and government could face reputational damage and operational disruptions if exploited. Additionally, the requirement for privileges and user interaction means internal users or editors with access to the plugin could inadvertently introduce malicious payloads, increasing insider threat risks. The absence of known exploits provides a window for proactive mitigation, but the lack of patches necessitates immediate risk management.

European organizations should immediately audit their web environments to identify installations of the Easy Flash Embed plugin. Given no patches are currently available, mitigation should focus on minimizing exposure: restrict plugin usage to trusted users only, implement strict input validation and output encoding on all user-generated content, and employ Content Security Policy (CSP) headers to limit script execution sources. Web Application Firewalls (WAFs) can be configured to detect and block common XSS payloads targeting this vulnerability. Organizations should also monitor logs for unusual activity related to the plugin and educate users with privileges about the risks of injecting untrusted content. Where possible, disable or remove the plugin until a secure version is released. Regular vulnerability scanning and penetration testing should include checks for stored XSS in this component. Finally, prepare incident response plans that include steps for containment and notification in case of exploitation, ensuring compliance with GDPR breach notification timelines.