CVE-2025-62671 is a stored Cross-site Scripting (XSS) vulnerability classified under CWE-79, found in the Cargo Extension of Mediawiki, an open-source wiki platform widely used for collaborative content management. The vulnerability stems from improper neutralization of input during web page generation, meaning that user-supplied data is not correctly sanitized or encoded before being embedded into web pages. This flaw allows an attacker to inject malicious JavaScript code that is stored persistently within the wiki content. When other users view the affected pages, the malicious script executes in their browsers, potentially leading to session hijacking, credential theft, unauthorized actions, or defacement. The vulnerability affects the master branch of the Cargo Extension, indicating it is present in the latest development versions rather than stable releases. The CVSS 4.0 base score is 6.9, reflecting a medium severity level, with an attack vector of network (remote exploitation), low attack complexity, no privileges or user interaction required, and limited impact on confidentiality, integrity, and availability. No known exploits have been reported in the wild yet. The lack of authentication and user interaction requirements increases the risk of automated exploitation. The Cargo Extension is used to manage structured data within Mediawiki, making this vulnerability particularly concerning for organizations relying on Mediawiki for critical documentation or knowledge bases. The Wikimedia Foundation assigned and published this vulnerability on October 18, 2025, but no patch links are currently available, indicating that remediation may still be in progress.

For European organizations, the impact of CVE-2025-62671 can be significant, especially for those using Mediawiki with the Cargo Extension in sensitive environments such as government portals, educational institutions, and research organizations. Exploitation could lead to unauthorized disclosure of sensitive information through session hijacking or theft of credentials. It could also allow attackers to perform actions on behalf of legitimate users, potentially altering or deleting critical content, undermining data integrity. The stored nature of the XSS means that once injected, the malicious payload can affect multiple users over time, increasing the attack's reach. Additionally, the presence of malicious scripts can damage organizational reputation and trust in publicly accessible wikis. While availability impact is limited, the confidentiality and integrity risks are moderate to high depending on the context of the deployed Mediawiki instance. The lack of authentication and user interaction requirements means attackers can exploit the vulnerability remotely and without user involvement, increasing the threat surface. European organizations that have integrated Mediawiki into their internal or external knowledge management systems should consider this vulnerability a priority for remediation to prevent potential data breaches or operational disruptions.

1. Monitor the Wikimedia Foundation and Cargo Extension repositories for official patches and apply them promptly once released. 2. Until patches are available, implement strict input validation and output encoding on all user-supplied data fields within the Cargo Extension to prevent malicious script injection. 3. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers accessing the wiki. 4. Conduct regular security audits and code reviews focusing on input handling in the Cargo Extension. 5. Limit write permissions to trusted users to reduce the risk of malicious content insertion. 6. Use web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting Mediawiki. 7. Educate users and administrators about the risks of XSS and encourage vigilance when reviewing content changes. 8. Implement monitoring and alerting for unusual activity or content changes within the wiki to detect potential exploitation early. 9. Consider isolating Mediawiki instances or restricting access to sensitive wikis to reduce exposure. 10. Regularly back up wiki content to enable recovery in case of defacement or data corruption.