CVE-2025-20382 Overview
CVE-2025-20382 is an unvalidated redirect vulnerability [CWE-601] affecting Splunk Enterprise and Splunk Cloud Platform. A low-privileged authenticated user without the admin or power role can create a views dashboard with a custom background using the data:image/png;base64 protocol. The crafted URL bypasses Splunk's external URL warning mechanism and redirects victims to an attacker-controlled site. Exploitation requires social engineering to trick an authenticated user into initiating the request within their browser. The issue was disclosed in Splunk Security Advisory SVD-2025-1201.
Critical Impact
Attackers can redirect authenticated Splunk users to malicious external sites, enabling phishing and credential theft while appearing to originate from a trusted Splunk domain.
Affected Products
- Splunk Enterprise versions below 10.0.2, 9.4.6, 9.3.8, and 9.2.10
- Splunk Cloud Platform versions below 10.1.2507.10, 10.0.2503.8, and 9.3.2411.120
- Deployments where non-admin, non-power users can author dashboards
Discovery Timeline
- 2025-12-03 - CVE-2025-20382 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-20382
Vulnerability Analysis
The flaw resides in the dashboard views rendering logic. Splunk normally warns users before navigating to external URLs, protecting against phishing pivots that abuse the trust context of an authenticated Splunk session. Dashboard authors can specify a custom background image using a URL. When a low-privileged user supplies a specifically crafted data:image/png;base64 URI, the external URL warning is not triggered, and the resulting navigation is treated as safe.
The attacker embeds redirect logic in the dashboard, then lures a victim into loading it. Because the request originates inside the victim's browser session with Splunk, downstream phishing pages inherit the credibility of the Splunk origin.
Root Cause
Splunk's URL validation fails to properly inspect content delivered through the data: URI scheme when used as a dashboard background. The external-URL warning filter matches on standard http(s):// targets but does not evaluate embedded or encoded destinations reachable through a data:image/png;base64 payload. This gap allows an authenticated author to smuggle a redirect target past the warning mechanism.
Attack Vector
Exploitation is remote and network-based but requires an authenticated Splunk account with dashboard-creation privileges. The attacker crafts a views dashboard containing the malicious data:image/png;base64 background, then phishes a higher-privileged victim into opening it. The victim's browser processes the crafted URL and issues an unvalidated redirect to the attacker's external site, where credential harvesting or session abuse can proceed. The attack requires user interaction and cannot be triggered at will by the authenticated author alone.
No public proof-of-concept or in-the-wild exploitation has been reported. Refer to Splunk Security Advisory SVD-2025-1201 for vendor-supplied technical detail.
Detection Methods for CVE-2025-20382
Indicators of Compromise
- Dashboard XML or JSON definitions containing data:image/png;base64 strings in background or image fields
- Audit log entries showing dashboard creation or modification by users lacking the admin or power role
- Outbound HTTP referrers from Splunk Web to unexpected external domains following dashboard views
- Unusual browser navigation chains that originate from a Splunk dashboard URL and terminate at credential-collection pages
Detection Strategies
- Search Splunk's _audit and _internal indexes for action=edit events on data/ui/views by non-admin, non-power users
- Alert on dashboard payloads containing data: URI schemes, especially base64-encoded content in background properties
- Correlate dashboard modification events with subsequent viewer sessions from privileged accounts
Monitoring Recommendations
- Enable and forward Splunk Web access logs to a centralized analytics platform to observe redirect patterns
- Review the roster of users with dashboard-creation capability and confirm role assignments follow least privilege
- Monitor browser-side telemetry for redirects sourced from Splunk origins to newly registered or low-reputation domains
How to Mitigate CVE-2025-20382
Immediate Actions Required
- Upgrade Splunk Enterprise to 10.0.2, 9.4.6, 9.3.8, 9.2.10, or later as applicable to your branch
- Confirm Splunk Cloud Platform is running 10.1.2507.10, 10.0.2503.8, 9.3.2411.120, or newer
- Audit dashboards created by non-admin, non-power users and remove any containing data: URI backgrounds
- Reinforce user awareness that authenticated Splunk links can still lead to phishing destinations
Patch Information
Splunk released fixes in Splunk Enterprise 10.0.2, 9.4.6, 9.3.8, and 9.2.10. Splunk Cloud Platform customers are patched in 10.1.2507.10, 10.0.2503.8, and 9.3.2411.120. Full details are available in Splunk Security Advisory SVD-2025-1201.
Workarounds
- Restrict dashboard creation privileges to trusted roles by revoking edit_ui or equivalent capabilities from low-privileged users
- Disable or limit custom background image capability in dashboard XML through role-based capability controls
- Enforce browser-side URL reputation checks or a secure web gateway to interrupt redirects to unknown external domains
# Configuration example: remove edit_ui capability from a custom role in authorize.conf
[role_dashboard_viewer]
edit_ui = disabled
importRoles = user
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
