CVE-2026-20252 Overview
CVE-2026-20252 is a Server-Side Request Forgery (SSRF) vulnerability in Splunk Enterprise and Splunk Cloud Platform. The flaw resides in the Dashboard Studio PDF export feature. A low-privileged authenticated user without the admin or power Splunk roles can coerce the server to issue HTTP requests to arbitrary internal destinations. The weakness maps to CWE-918.
Critical Impact
Authenticated attackers can pivot from a low-privileged Splunk account to reach internal services, cloud metadata endpoints, and other network resources reachable from the Splunk PDF export service.
Affected Products
- Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13
- Splunk Cloud Platform versions below 10.4.2604.3, 10.3.2512.12, 10.2.2510.14, 10.1.2507.22, and 9.3.2411.132
- Dashboard Studio PDF export component
Discovery Timeline
- 2026-06-10 - CVE-2026-20252 published to NVD
- 2026-06-10 - Last updated in NVD database
Technical Details for CVE-2026-20252
Vulnerability Analysis
The Dashboard Studio PDF export service in Splunk fetches remote resources during PDF rendering. Splunk attempts to constrain outbound requests using a trusted-domain allowlist. The allowlist enforcement is broken in two ways that combine into an SSRF primitive.
An authenticated user submits a crafted PDF export request that references an attacker-controlled URL. The export backend issues an HTTP request on behalf of the server, allowing access to network destinations that are not reachable from the user's own network position. This includes loopback services, cloud instance metadata, and internal management interfaces.
The issue affects confidentiality of internal services and can be used to read response bodies returned through the export pipeline, while integrity and availability impact remain limited.
Root Cause
The trusted-domain validation uses a prefix match. An attacker registers a hostname such as docs.splunk.com.evil.com, which begins with the expected allowlisted string but resolves to attacker-controlled infrastructure. The validator accepts the hostname because string prefix comparison does not enforce a domain boundary.
The second defect is in the HTTP client behavior. The PDF export service follows HTTP 3xx redirects automatically and does not re-apply the allowlist check to each redirect target. An attacker hosts an allowlisted-looking URL that returns a 302 response pointing to http://169.254.169.254/ or other internal endpoints.
Attack Vector
Exploitation requires a valid Splunk session for a non-admin, non-power user. The attacker invokes the Dashboard Studio PDF export feature with a URL that satisfies the prefix check. The server fetches the URL, follows the redirect chain, and returns content from the final destination to the export pipeline. The vulnerability is reachable over the network and requires no user interaction.
Verified exploitation code is not available. See the Splunk Security Advisory SVD-2026-0602 for vendor technical detail.
Detection Methods for CVE-2026-20252
Indicators of Compromise
- Outbound HTTP requests from the Splunk PDF export service to non-Splunk destinations, especially RFC1918 ranges, link-local 169.254.169.254, or loopback addresses
- Dashboard Studio PDF export jobs initiated by users that do not hold the admin or power roles
- URLs in export job parameters containing allowlisted strings followed by additional domain labels, such as splunk.com.<attacker>.tld
Detection Strategies
- Inspect Splunk internal audit logs for action=pdf_export events combined with unusual target_url values
- Correlate PDF export activity with network egress logs from the Splunk host to identify redirect chains terminating at internal IP ranges
- Alert on responses to PDF export requests that contain cloud metadata response signatures, such as IAM credential JSON structures
Monitoring Recommendations
- Capture and retain HTTP client logs from the Dashboard Studio PDF rendering component
- Forward Splunk _audit and _internal indexes to a separate analysis tier so they remain available if the Splunk instance is compromised
- Baseline normal PDF export volume per user and alert on outliers from low-privileged accounts
How to Mitigate CVE-2026-20252
Immediate Actions Required
- Upgrade Splunk Enterprise to 10.2.4, 10.0.7, 9.4.12, 9.3.13, or later as appropriate for your release branch
- Confirm Splunk Cloud Platform instances are on 10.4.2604.3, 10.3.2512.12, 10.2.2510.14, 10.1.2507.22, 9.3.2411.132, or later
- Audit role assignments and remove unnecessary access to Dashboard Studio features for low-privileged accounts
Patch Information
Splunk has released fixed versions addressing the prefix-match validation and the unchecked redirect following behavior. Refer to Splunk Security Advisory SVD-2026-0602 for the complete fixed-version matrix and upgrade guidance.
Workarounds
- Disable the Dashboard Studio PDF export feature until patches are applied
- Restrict egress from Splunk search head and PDF export hosts to only the destinations required for operation, blocking access to instance metadata endpoints and internal management networks
- Place Splunk behind an egress proxy that performs strict allowlist enforcement with domain-boundary matching and disallows automatic redirect following
# Example egress restriction enforced at the host firewall (Linux nftables)
# Block access from the Splunk service account to cloud metadata
nft add rule inet filter output skuid splunk ip daddr 169.254.169.254 drop
nft add rule inet filter output skuid splunk ip daddr 127.0.0.0/8 drop
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
