CVE-2025-20382 is a vulnerability affecting multiple versions of Splunk Enterprise and Splunk Cloud Platform, where a low-privileged user can create a views dashboard with a custom background image using the 'data:image/png;base64' protocol. This crafted input can bypass the built-in external URL warning mechanism in Splunk, enabling an unvalidated redirect to an external site controlled by an attacker. The vulnerability arises because the application accepts user-controlled input specifying a link to an external site and uses it in a redirect without proper validation. The attacker must have at least low-level authenticated access (without admin or power roles) and must phish an authenticated user to trigger the redirect via their browser. The vulnerability does not allow unauthenticated exploitation or direct arbitrary redirects by the attacker without user interaction. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N) reflects that the attack is network-based, requires low privileges, user interaction, and results in limited confidentiality impact without affecting integrity or availability. No public exploits are known, and the vulnerability primarily facilitates phishing by making malicious redirects appear legitimate within the Splunk interface.

For European organizations using affected versions of Splunk Enterprise or Splunk Cloud Platform, this vulnerability could increase the risk of successful phishing attacks targeting their employees or administrators. Since Splunk is widely used for security information and event management (SIEM), attackers leveraging this redirect could potentially trick users into visiting malicious sites that harvest credentials or deploy malware, undermining organizational security. The impact on confidentiality is low but non-negligible, as phishing can lead to credential compromise or lateral movement. The requirement for authenticated access and user interaction limits the scope, but organizations with large Splunk deployments and many users may face increased exposure. Additionally, the trust placed in Splunk dashboards by security teams could be exploited to bypass user suspicion. However, no direct compromise of Splunk data or system integrity is indicated by this vulnerability.

European organizations should prioritize upgrading affected Splunk Enterprise and Cloud Platform instances to versions 10.0.2, 9.4.6, 9.3.8, 9.2.10 or later, as these contain fixes for the vulnerability. Until patches are applied, administrators should restrict dashboard creation permissions to trusted users only, minimizing the risk of malicious dashboard content. Implement strict role-based access controls to limit low-privileged user capabilities. Educate users and administrators about phishing risks, emphasizing caution with unexpected redirects or unusual dashboard content. Monitor Splunk logs for unusual dashboard creation or modification activities. Consider deploying web filtering or endpoint protection solutions that can detect and block known phishing URLs. Finally, review and tighten Splunk’s external URL handling policies if configurable, to add additional validation or warnings.