CVE-2025-20385 is a stored cross-site scripting (XSS) vulnerability affecting Splunk Enterprise versions below 10.0.2, 9.4.6, 9.3.8, and 9.2.10, as well as Splunk Cloud Platform versions below 10.1.2507.6, 10.0.2503.7, and 9.3.2411.117. The vulnerability arises because the software does not properly neutralize user-controllable input before embedding it into web pages served to other users. Specifically, a user with the 'admin_all_objects' capability can craft a malicious payload within the href attribute of an anchor tag in a navigation bar collection. When other users view the affected page, the malicious JavaScript executes in their browsers, potentially leading to session hijacking, credential theft, or other client-side attacks. However, exploitation requires the attacker to have high privileges and necessitates user interaction to trigger the payload. The CVSS v3.1 base score is 2.4, reflecting low severity due to limited impact on confidentiality and no impact on integrity or availability. No known active exploits have been reported. The vulnerability underscores the importance of input validation and output encoding in web applications, especially those handling sensitive operational data like Splunk. Vendors have released patches in the specified versions to address this issue.

For European organizations, the primary impact is the potential for unauthorized JavaScript execution in the browsers of users who access the compromised navigation bar collections. This could lead to limited confidentiality breaches such as session token theft or unauthorized actions performed in the context of the victim user. However, since exploitation requires an attacker to already have high-level administrative privileges and user interaction, the risk of widespread compromise is low. Organizations relying on Splunk for security monitoring and operational intelligence could face targeted attacks aimed at elevating privileges or stealing sensitive monitoring data if the vulnerability is exploited. The impact on integrity and availability is negligible. Nonetheless, in environments with strict compliance requirements (e.g., GDPR), even low-severity vulnerabilities that could lead to data leakage must be addressed promptly. The absence of known exploits in the wild reduces immediate risk but does not eliminate the need for remediation.

1. Apply the vendor-provided patches by upgrading Splunk Enterprise to version 10.0.2 or later, 9.4.6 or later, 9.3.8 or later, and 9.2.10 or later, or the corresponding patched versions of Splunk Cloud Platform. 2. Restrict the assignment of the 'admin_all_objects' capability strictly to trusted and necessary personnel to reduce the attack surface. 3. Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers accessing Splunk web interfaces. 4. Regularly audit Splunk navigation bar collections and other user-controllable inputs for suspicious or unauthorized modifications. 5. Educate users with high privileges about phishing and social engineering risks to prevent attackers from gaining initial access. 6. Monitor Splunk logs for unusual activity related to navigation bar modifications or administrative actions. 7. Consider deploying web application firewalls (WAFs) with rules to detect and block XSS payloads targeting Splunk interfaces. These steps go beyond generic advice by focusing on privilege management, input auditing, and layered defenses specific to the Splunk environment.