CVE-2025-24853 is a cross-site scripting (XSS) vulnerability classified under CWE-79 affecting the Apache JSPWiki software maintained by the Apache Software Foundation. The vulnerability arises from improper neutralization of input during web page generation, specifically when users create header links using the wiki markup syntax or when content is parsed via the markdown parser. An attacker can craft a malicious request embedding JavaScript code within these inputs, which JSPWiki fails to sanitize properly. When a victim views the affected wiki page, the malicious script executes in their browser context, potentially allowing the attacker to steal sensitive information such as session cookies, authentication tokens, or other data accessible in the browser environment. The vulnerability does not require any privileges or user interaction to exploit, making it remotely exploitable over the network. The CVSS v3.1 base score is 7.5 (high), reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, no confidentiality impact, but high integrity impact and no availability impact. The vulnerability was reserved in January 2025 and published in July 2025. The Apache JSPWiki team has addressed the issue in version 2.12.3, recommending all users upgrade to this or later versions to mitigate the risk. No public exploits have been reported yet, but the nature of XSS vulnerabilities means exploitation is straightforward once the vulnerability is known.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of sensitive information accessed via JSPWiki platforms. Since JSPWiki is often used for internal documentation, knowledge sharing, and collaboration, exploitation could lead to session hijacking, unauthorized access to internal resources, or leakage of confidential business information. The lack of required authentication or user interaction increases the risk of widespread exploitation, especially in organizations with publicly accessible JSPWiki instances. This could undermine trust in internal communication tools and potentially facilitate further attacks such as phishing or lateral movement within networks. The impact is particularly critical for sectors handling sensitive data, including finance, government, healthcare, and critical infrastructure. Additionally, the vulnerability could be leveraged to target European Union institutions or companies involved in cross-border collaborations, amplifying the potential damage.

The primary and most effective mitigation is to upgrade Apache JSPWiki to version 2.12.3 or later, where the vulnerability has been fixed. Organizations should prioritize this upgrade in their patch management cycles. Beyond upgrading, administrators should implement strict input validation and output encoding on wiki markup inputs, especially for header links and markdown content, to prevent injection of malicious scripts. Employing Content Security Policy (CSP) headers can help mitigate the impact of any residual XSS by restricting script execution sources. Monitoring web server logs and application logs for unusual or suspicious wiki content submissions can help detect attempted exploitation. Additionally, educating users about the risks of clicking unknown or suspicious links within wiki pages can reduce the likelihood of successful attacks. For organizations with public-facing JSPWiki instances, consider restricting access or implementing web application firewalls (WAFs) with rules to detect and block XSS payloads targeting JSPWiki.