Splunk Enterprise 10.x Low-Priv Exfil via // URLs in Dashboards
CVE-2026-20256 Published on June 10, 2026
Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise
In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could cause data exfiltration through classic dashboards by redirecting a victim to an external site using a protocol-relative URL in a drill-down link.<br><br>The vulnerability exists because the URL classifier in classic dashboards only recognizes `http://` and `https://` schemes when checking for external URLs. Protocol-relative URLs such as `//attacker.com` bypass this check entirely, and Splunk Web does not show the external-navigation warning dialog to the victim.
Weakness Type
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2026-20256
stack.watch emails you whenever new vulnerabilities are published in Splunk or Splunk Cloud Platform. Just hit a watch button to start following.
Affected Versions
Splunk Enterprise:- Version 10.2 and below 10.2.4 is affected.
- Version 10.0 and below 10.0.7 is affected.
- Version 9.4 and below 9.4.12 is affected.
- Version 9.3 and below 9.3.13 is affected.
- Version 10.3.2512 and below 10.3.2512.13 is affected.
- Version 10.2.2510 and below 10.2.2510.15 is affected.
- Version 10.1.2507 and below 10.1.2507.23 is affected.
- Version 9.3.2411 and below 9.3.2411.132 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.