Medium severity · published Jun 10, 2026
CVE-2026-20256
Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise
5.7
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SC
Splunk Cloud Platform · Splunk
10.3.2512 before 10.3.2512.13; 10.2.2510 before 10.2.2510.15; 10.1.2507 before 10.1.2507.23; 9.3.2411 before 9.3.2411.132 · source: vendor, NVD
SE
Splunk Enterprise · Splunk
10.2 before 10.2.4; 10.0 before 10.0.7; 9.4 before 9.4.12; 9.3 before 9.3.13 · source: vendor
SP
Splunk · Splunk
9.3.0 before 9.3.13; 9.4.0 before 9.4.12; 10.0.0 before 10.0.7; 10.2.0 before 10.2.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20256
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20256
Vendor Advisory
https://advisory.splunk.com/advisories/SVD-2026-0606
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