CVE-2022-29258 is a cross-site scripting (XSS) vulnerability affecting the XWiki Platform, specifically within the Filter UI component. The vulnerability arises from improper neutralization of script-related HTML tags in the Filter.FilterStreamDescriptorForm wiki page, which is used to configure input and output streams for filters. This flaw allows malicious actors to inject arbitrary scripts into various form fields displayed on the application's home page. The vulnerability affects multiple versions of the XWiki Platform, including versions from 5.4.4 up to but not including 12.10.11, and from 13.0.0 up to but not including 13.4.7 and 13.10.3. The root cause is the failure to properly encode or escape user-supplied input before rendering it in the web interface, violating CWE-80 and CWE-116. Exploitation does not require authentication or complex user interaction beyond visiting a crafted page or submitting malicious input. Although no known exploits have been reported in the wild, the vulnerability is considered medium severity and has been patched in later versions. A practical workaround involves manually editing the vulnerable wiki page to sanitize inputs as per guidance in the GitHub Security Advisory. The vulnerability primarily impacts the confidentiality and integrity of user sessions by enabling script injection, which could lead to session hijacking, defacement, or redirection attacks. The availability impact is limited but could be indirectly affected if malicious scripts disrupt normal operations.

For European organizations using XWiki Platform, this vulnerability poses a moderate risk primarily to web application security. XWiki is widely used in enterprise collaboration, documentation, and knowledge management, often containing sensitive internal information. Successful exploitation could allow attackers to execute arbitrary JavaScript in the context of authenticated users, potentially leading to session hijacking, credential theft, or unauthorized actions within the platform. This could result in data leakage, loss of trust, and compliance violations under regulations such as GDPR. The impact is heightened in sectors with stringent data protection requirements, including government, finance, and healthcare institutions. While the vulnerability does not directly compromise backend systems or databases, the ability to manipulate the user interface and steal session tokens can facilitate further attacks. The lack of known exploits suggests limited active targeting, but the medium severity rating and ease of exploitation warrant prompt remediation to prevent potential abuse.

1. Upgrade XWiki Platform to the latest patched versions: 12.10.11, 13.4.7, 13.10.3, or later, which contain fixes for this vulnerability. 2. If immediate upgrade is not feasible, apply the manual workaround by editing the Filter.FilterStreamDescriptorForm wiki page to sanitize all form fields according to the official GitHub Security Advisory instructions. 3. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts within the XWiki web application. 4. Conduct regular security audits and code reviews focusing on input validation and output encoding in custom wiki pages or extensions. 5. Educate users and administrators about the risks of XSS and encourage cautious handling of user-generated content. 6. Monitor web application logs for unusual input patterns or script injection attempts. 7. Employ web application firewalls (WAF) with rules tailored to detect and block XSS payloads targeting XWiki endpoints. These steps go beyond generic advice by focusing on both immediate remediation and long-term security hygiene specific to XWiki deployments.