CVE-2025-24853: 
Java vulnerability analysis and mitigation

CVE-2025-24853 is a Cross-Site Scripting (XSS) vulnerability in Apache JSPWiki affecting all versions up to and including 2.12.2. A carefully crafted request when creating a header link using wiki markup syntax allows an attacker to execute arbitrary JavaScript in a victim's browser and potentially obtain sensitive information. The vulnerability was also found to affect the markdown parser in JSPWiki. Disclosed on July 30, 2025, it carries a CVSS v3.1 base score of 7.5 (High) (OSS-Security, Apache JSPWiki Advisory).

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-Site Scripting). The root cause is insufficient sanitization of user-supplied input in the wiki markup header link parser and the markdown parser, allowing injection of malicious JavaScript. An attacker can craft a specially formatted header link in wiki or markdown syntax that, when rendered in a victim's browser, executes the injected script. No authentication or user interaction is required for the attack to be staged, though a victim must view the malicious content for the script to execute (OSS-Security, Apache JSPWiki Advisory).

Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of a victim's browser session, potentially enabling session hijacking, credential theft, sensitive information disclosure, or unauthorized actions performed on behalf of the victim. The attack can be delivered network-wide with low complexity and requires no privileges, making it accessible to unauthenticated attackers. Both the wiki markup and markdown parsers are affected, broadening the attack surface across JSPWiki deployments (OSS-Security, Feedly).

There is no public proof-of-concept exploit code and no evidence of in-the-wild exploitation at this time. The vulnerability was discovered and reported by XBOW Security (https://xbow.com). The EPSS score is approximately 0.003 (0.3%), indicating a low probability of exploitation in the near term. The vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (OSS-Security, Feedly).

1. Reconnaissance: Identify publicly accessible Apache JSPWiki instances running versions up to 2.12.2 using web search or scanning tools.
2. Craft malicious wiki markup: Create a header link in wiki markup or markdown syntax that embeds a JavaScript payload, e.g., a header link formatted to inject <script> tags or event handlers that bypass the parser's sanitization.
3. Inject the payload: Submit the crafted content to a JSPWiki page (e.g., by editing a wiki page or creating a new one) so the malicious header link is stored or reflected in the application.
4. Deliver to victim: Lure a victim (e.g., another wiki user or administrator) to view the page containing the malicious header link.
5. Execute JavaScript: When the victim's browser renders the page, the injected JavaScript executes in their browser context, potentially stealing session cookies, credentials, or other sensitive information and sending it to an attacker-controlled server (OSS-Security, Apache JSPWiki Advisory).

• Logs: Web server or application logs showing unusual wiki page edits or submissions containing JavaScript keywords (<script>, onerror, onload, javascript:) within header link markup fields.
• Network: Outbound HTTP requests from victim browsers to unexpected external domains shortly after viewing wiki pages, potentially indicating data exfiltration via XSS.
• File System: Wiki page content files or database entries containing embedded JavaScript or encoded script payloads within header link syntax.
• Application: Unexpected changes to wiki page content, particularly in header sections, containing HTML event handlers or script tags.

Apache JSPWiki users should upgrade to version 2.12.3 or later, which contains fixes for both the wiki markup header link parser and the markdown parser (OSS-Security, Apache JSPWiki Advisory). As interim mitigations, administrators should restrict wiki editing privileges to trusted users only, implement a Content Security Policy (CSP) header to limit script execution, and monitor wiki content for suspicious script injections. Input validation and output encoding for wiki markup and markdown content should be enforced at the application layer.

The vulnerability was disclosed via the Apache Security mailing list and oss-security on July 30, 2025, by Juan Pablo Santos Rodríguez on behalf of the JSPWiki team, crediting XBOW Security as the finder (OSS-Security). Brief community discussion was noted on Bluesky and security aggregator sites shortly after disclosure. No significant vendor statements beyond the official advisory or notable researcher commentary have been identified.