CVE-2026-20256

Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise

Published Jun 10, 2026 CVSS 3.1 · 5.7 Medium EPSS < 1% KEV · Not listed

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.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Splunk

Splunk Enterprise

affected

Version	Status	Constraints
`10.2`	affected	< 10.2.4
`10.0`	affected	< 10.0.7
`9.4`	affected	< 9.4.12
`9.3`	affected	< 9.3.13

Splunk

Splunk Cloud Platform

affected

Version	Status	Constraints
`10.3.2512`	affected	< 10.3.2512.13
`10.2.2510`	affected	< 10.2.2510.15
`10.1.2507`	affected	< 10.1.2507.23
`9.3.2411`	affected	< 9.3.2411.132

Configuration 1 [-]

OR	cpe:2.3:a:splunk:splunk:::::enterprise:::*
	cpe:2.3:a:splunk:splunk:::::enterprise:::*
	cpe:2.3:a:splunk:splunk:::::enterprise:::*
	cpe:2.3:a:splunk:splunk:::::enterprise:::*

Configuration 2 [-]

OR	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
	cpe:2.3:a:splunk:splunk_cloud_platform::::::::

No data.

Vendor Product Versions

Splunk

Splunk Cloud Platform

Version	Status	Scheme	Platform
`[10.3.2512,10.3.2512.13)`	affected	generic	—
`[10.2.2510,10.2.2510.15)`	affected	generic	—
`[10.1.2507,10.1.2507.23)`	affected	generic	—
`[9.3.2411,9.3.2411.132)`	affected	generic	—

Splunk

Splunk Enterprise

Version	Status	Scheme	Platform
`[10.2,10.2.4)`	affected	generic	—
`[10.0,10.0.7)`	affected	generic	—
`[9.4,9.4.12)`	affected	generic	—
`[9.3,9.3.13)`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.361% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://advisory.splunk.com/advisories/SVD-2026-0606

History

Nov 10, 2026 9:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jun 15, 2026 2:45 PM First appearance in the feed. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Splunk splunk
CPEs		cpe:2.3:a:splunk:splunk:::::enterprise:::* cpe:2.3:a:splunk:splunk_cloud_platform::::::::
Vendors & Products		Splunk splunk

Jun 10, 2026 7:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Splunk Splunk splunk Cloud Platform Splunk splunk Enterprise
Vendors & Products		Splunk Splunk splunk Cloud Platform Splunk splunk Enterprise

Jun 10, 2026 6:15 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise
Weaknesses		CWE-20
References		https://advisory.splunk.com/advisories/SVD-2026-0606
Metrics		cvssV3_1 `{'score': 5.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N'}`