CVE-2026-20256 json
Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise
published 2026-06-10 4 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-36080
- cvss
- 5.7
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Splunk Splunk Enterprise 9.3.13, 9.4.12, 10.0.7, 10.2.4
- Splunk Splunk Cloud Platform 9.3.2411.132, 10.1.2507.23, 10.2.2510.15, 10.3.2512.13
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4 mo ago
Exploit prediction
0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N |
Affected products
- Splunk Splunk Enterprise
- Splunk Splunk Cloud Platform
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
advisory.splunk.com
/advisories/SVD-2026-0606
vendor-advisory
Sources
- CVE List CVE-2026-20256
- NVD CVE-2026-20256
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.