CVE-2025-54297 is a stored Cross-Site Scripting (XSS) vulnerability identified in the CComment component versions 5.0.0 through 6.1.14 for the Joomla content management system (CMS). This vulnerability arises due to improper neutralization of input during web page generation (CWE-79), allowing malicious actors to inject and persist arbitrary scripts within the comment sections managed by the CComment component. When a user accesses a page containing the maliciously crafted comment, the embedded script executes in the context of the victim's browser. This can lead to session hijacking, credential theft, defacement, or redirection to malicious sites. The vulnerability is classified as high severity with a CVSS 4.0 base score of 7.0, reflecting a network attack vector but requiring high attack complexity, high privileges, and user interaction, with high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects a widely used Joomla extension, which is popular among website administrators for managing user comments, making it a significant risk for websites relying on this component without appropriate mitigations.

For European organizations, especially those operating public-facing websites using Joomla with the vulnerable CComment component, this vulnerability poses a significant risk. Exploitation could lead to unauthorized access to user sessions, data leakage, and potential defacement or malware distribution through trusted websites. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR breaches due to data exposure), and disrupt business operations. Given the high privileges required for exploitation, internal threat actors or compromised administrators pose a notable risk. Additionally, the requirement for user interaction means phishing or social engineering could facilitate exploitation. Sectors such as e-commerce, government portals, educational institutions, and media outlets in Europe that rely on Joomla for content management are particularly vulnerable. The persistence of malicious scripts can also facilitate long-term espionage or targeted attacks against European entities.

European organizations should immediately audit their Joomla installations to identify the presence of the CComment component within the affected version range (5.0.0 to 6.1.14). Until an official patch is released, organizations should implement strict input validation and output encoding on all user-generated content fields, especially comments, to neutralize potentially malicious scripts. Web Application Firewalls (WAFs) should be configured with rules to detect and block typical XSS payloads targeting comment sections. Administrators should enforce the principle of least privilege, limiting high-level access to trusted personnel only, and monitor logs for suspicious comment submissions or administrative actions. User awareness training should emphasize the risks of interacting with suspicious content. Additionally, organizations should consider temporarily disabling the CComment component or replacing it with alternative, secure commenting solutions. Regular backups and incident response plans should be updated to address potential exploitation scenarios.