CVE-2025-62671 identifies a stored Cross-site Scripting (XSS) vulnerability in the Cargo Extension of Mediawiki, a widely used open-source wiki platform maintained by The Wikimedia Foundation. The vulnerability arises from improper neutralization of input during web page generation, classified under CWE-79. Specifically, the Cargo Extension fails to adequately sanitize or encode user-supplied data before rendering it in web pages, allowing attackers to inject malicious JavaScript code that is stored persistently and executed whenever a user accesses the affected page. This vulnerability affects the master branch of the Cargo Extension as of the published date (October 18, 2025). The CVSS 4.0 vector indicates the attack can be performed remotely (AV:N) with low attack complexity (AC:L), requiring no privileges (PR:N) or user interaction (UI:N). The impact on confidentiality, integrity, and availability is low to limited (VC:L, VI:L, VA:L), and the scope is limited (SC:L), but the vulnerability can still lead to session hijacking, credential theft, or content manipulation. No patches or known exploits are currently reported, but the risk remains significant due to the extension's usage in various Mediawiki deployments. The vulnerability's presence in a core extension used for structured data management in Mediawiki makes it a concern for organizations relying on Mediawiki for knowledge management and collaboration.

For European organizations, the impact of CVE-2025-62671 can be substantial, particularly for government agencies, educational institutions, cultural organizations, and enterprises that use Mediawiki with the Cargo Extension for documentation, knowledge bases, or collaborative projects. Exploitation of this stored XSS vulnerability could allow attackers to execute arbitrary scripts in the context of users' browsers, leading to session hijacking, unauthorized data access, defacement of content, or distribution of malware. This can undermine trust in publicly accessible wikis and internal knowledge repositories, potentially causing reputational damage and operational disruption. Since the vulnerability requires no authentication or user interaction, it can be exploited by remote attackers without insider access, increasing the attack surface. The medium severity rating reflects a moderate but meaningful risk, especially in environments where sensitive or critical information is managed via Mediawiki. Additionally, the lack of known exploits currently provides a window for proactive mitigation before widespread exploitation occurs.

1. Monitor official Wikimedia Foundation channels for patches or updates to the Cargo Extension and apply them promptly once available. 2. Until a patch is released, consider disabling or restricting the use of the Cargo Extension in Mediawiki deployments, especially on public-facing or sensitive wikis. 3. Implement strict input validation and output encoding on all user-supplied data rendered by the Cargo Extension to prevent injection of malicious scripts. 4. Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. 5. Conduct regular security audits and code reviews of Mediawiki extensions to identify and remediate similar vulnerabilities. 6. Educate users and administrators about the risks of XSS and encourage vigilance for suspicious behavior or content changes. 7. Use web application firewalls (WAFs) with rules tuned to detect and block common XSS attack patterns targeting Mediawiki. 8. Maintain comprehensive logging and monitoring to detect exploitation attempts and respond swiftly to incidents.