CVE-2025-24853 is a cross-site scripting (XSS) vulnerability identified in the Apache Software Foundation's Apache JSPWiki product. The vulnerability arises from improper neutralization of input during web page generation, specifically when users create header links using the wiki markup syntax. An attacker can craft a malicious request that injects JavaScript code into these header links. When a victim views the affected wiki page, the injected script executes in their browser context, potentially exposing sensitive information such as session tokens, cookies, or other private data accessible via the browser. Further investigation revealed that the markdown parser component of JSPWiki is also vulnerable to similar injection attacks, broadening the attack surface. This vulnerability is categorized under CWE-79, which pertains to improper input sanitization leading to XSS. Although no CVSS score has been assigned yet, the Apache JSPWiki team has addressed the issue in version 2.12.3 and later, recommending all users upgrade to these versions to mitigate the risk. There are currently no known exploits in the wild, but the vulnerability's nature makes it a significant risk for web applications relying on JSPWiki for collaborative content management.

For European organizations utilizing Apache JSPWiki, this vulnerability poses a notable risk to confidentiality and integrity of user data. Successful exploitation could allow attackers to hijack user sessions, steal authentication credentials, or perform actions on behalf of legitimate users, potentially leading to unauthorized access to sensitive internal information. This is particularly concerning for organizations in sectors such as government, finance, healthcare, and critical infrastructure, where sensitive data is frequently managed via collaborative platforms. Additionally, the exploitation could facilitate phishing or social engineering campaigns by injecting misleading content into wiki pages. The impact extends beyond individual users to organizational reputation and compliance, especially under GDPR regulations where data breaches involving personal data can lead to significant fines and legal consequences. The absence of known exploits currently provides a window for proactive mitigation, but the ease of exploitation inherent in XSS vulnerabilities means attackers could develop exploits rapidly once the vulnerability details are publicized.

European organizations should immediately verify their Apache JSPWiki versions and upgrade to version 2.12.3 or later, where the vulnerability has been patched. Beyond upgrading, organizations should implement strict Content Security Policies (CSP) to restrict the execution of unauthorized scripts within their web applications. Input validation and output encoding should be enforced at the application level to sanitize all user-generated content, especially in wiki markup and markdown inputs. Regular security audits and penetration testing focusing on web application inputs can help detect similar vulnerabilities early. Additionally, organizations should monitor their web logs for unusual or suspicious requests targeting wiki header links or markdown content. User awareness training about phishing risks associated with manipulated wiki content can reduce the likelihood of successful exploitation. Finally, maintaining an up-to-date inventory of web applications and their components will facilitate timely patch management and vulnerability response.