Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-20256

Severity CVSS v4.0:
Pending analysis
Type:
CWE-20 Input Validation
Publication date:
10/06/2026
Last modified:
15/06/2026

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.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.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.70 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x
5.70
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:* 9.3.0 (including) 9.3.13 (excluding)
cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:* 9.4.0 (including) 9.4.12 (excluding)
cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:* 10.0.0 (including) 10.0.7 (excluding)
cpe:2.3:a:splunk:splunk:*:*:*:*:enterprise:*:*:* 10.2.0 (including) 10.2.4 (excluding)
cpe:2.3:a:splunk:splunk_cloud_platform:*:*:*:*:*:*:*:* 9.3.2411 (including) 9.3.2411.132 (excluding)
cpe:2.3:a:splunk:splunk_cloud_platform:*:*:*:*:*:*:*:* 10.1.2507 (including) 10.1.2507.23 (excluding)
cpe:2.3:a:splunk:splunk_cloud_platform:*:*:*:*:*:*:*:* 10.2.2510 (including) 10.2.2510.15 (excluding)
cpe:2.3:a:splunk:splunk_cloud_platform:*:*:*:*:*:*:*:* 10.3.2512 (including) 10.3.2512.13 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools