Vulnerability Report

CVE-2026-20256

Title: Splunk Classic Dashboard Data Exfiltration (Protocol-Relative URL)

Input Validation Error

Proof Of Concept

No public PoC currently indexed for CVE-2026-20256.

CWE Category CWE-20
Published Date Jun 10, 2026
Modified Date Jun 15, 2026
Exploit Status Not Found
Score 5.7 CVSS v3.1
Exploit Probability (EPSS)
0.25%

Vulnerability Summary

CVE-2026-20256: 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.

Impacted Vendors

S
splunk 2
J
jenkins 1

Reference Links

https://advisory.splunk.com/advisories/SVD-2026-0606
CVSS v3.1
Source Entity [email protected]
Severity MEDIUM
5.7
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
REQUIRED
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-20256 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction REQUIRED
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

Affected Stack

No specific products linked.