CVE-2025-20382: 
Splunk Enterprise vulnerability analysis and mitigation

CVE-2025-20382 is an open redirect vulnerability (CWE-601) in Splunk Enterprise and Splunk Cloud Platform that allows a low-privileged authenticated user to create a views dashboard with a custom background using the data:image/png;base64 protocol, bypassing Splunk's external URL warning mechanism and redirecting victims to malicious external sites. It was disclosed on December 3, 2025, and affects Splunk Enterprise versions below 10.0.2, 9.4.6, 9.3.8, and 9.2.10, and Splunk Cloud Platform versions below 10.1.2507.10, 10.0.2503.8, and 9.3.2411.120. The CVSS v3.1 base score is 5.4 (Medium) per NVD, while the CNA (Cisco Systems) assigned a lower score of 3.5 (Low) (Splunk Advisory).

The root cause is insufficient URL validation (CWE-601) in Splunk's dashboard views feature, where the application fails to properly validate or restrict URLs embedded as custom dashboard backgrounds. An attacker exploits this by crafting a dashboard view that uses the data:image/png;base64 protocol in a way that encodes a redirect to an external malicious URL, circumventing Splunk's built-in external URL warning mechanism. Exploitation requires the attacker to hold at minimum a low-privileged Splunk account (not "admin" or "power" role) and to phish a victim user into clicking a link or initiating a browser request that triggers the malicious dashboard. No public proof-of-concept code has been identified (Splunk Advisory).

Successful exploitation results in an unvalidated redirect of an authenticated victim user to an attacker-controlled external site, enabling phishing, credential harvesting, or malware delivery. The confidentiality and integrity impacts are rated low — there is limited direct data exposure from the Splunk instance itself, but the redirect can facilitate secondary attacks against the victim. Availability is not impacted, and the vulnerability does not grant the attacker direct access to Splunk data or administrative functions (Splunk Advisory).

There is no evidence of public proof-of-concept exploit code or active in-the-wild exploitation as of the time of disclosure. The vulnerability requires an authenticated low-privileged attacker and victim user interaction (phishing), limiting its exploitability. The EPSS score is approximately 0.025% (0.000250), indicating a very low probability of exploitation in the near term. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (Splunk Advisory).

1. Obtain low-privileged access: Acquire a Splunk account that does not hold the "admin" or "power" role on a vulnerable Splunk Enterprise or Cloud Platform instance.
2. Create a malicious dashboard: In the Splunk web interface, create a new views dashboard and set a custom background using the data:image/png;base64 protocol with a specially crafted URL that encodes a redirect to an attacker-controlled external site.
3. Craft a phishing link: Generate a shareable link to the malicious dashboard within the Splunk instance.
4. Phish the victim: Send the crafted link to a target authenticated Splunk user via email, chat, or other social engineering channels, tricking them into clicking it.
5. Redirect achieved: When the victim opens the link in their browser, the dashboard's custom background triggers the unvalidated redirect, sending the victim's browser to the attacker's external malicious site (e.g., a credential harvesting page) (Splunk Advisory).

• Logs: Splunk internal audit logs showing dashboard creation or modification events by low-privileged users, particularly dashboards with data:image/png;base64 strings in background URL fields.
• Network: Outbound HTTP/HTTPS requests from victim browsers to unexpected external domains immediately following access to a Splunk dashboard URL.
• Splunk Activity: Unusual dashboard view creation by non-admin, non-power users; review _audit index for action=edit or action=create events on dashboard objects with suspicious URL content.

Splunk has released patched versions addressing this vulnerability. Users should upgrade to Splunk Enterprise 10.0.2, 9.4.6, 9.3.8, or 9.2.10, or Splunk Cloud Platform 10.1.2507.10, 10.0.2503.8, or 9.3.2411.120. As interim mitigations, administrators should restrict dashboard creation permissions to trusted users, implement user awareness training regarding phishing attempts, and monitor for unusual dashboard creation activity by low-privileged accounts. Network and browser security controls (e.g., web proxies with URL filtering) can also help prevent unintended external redirects (Splunk Advisory).