CVE-2026-20254: Information Disclosure through External Content Restriction Bypass in Splunk Enterprise

Severity: medium (CVSS 5.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-10 · updated 2026-06-17
Weakness: CWE-20

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 craft a malicious classic dashboard that exfiltrates sensitive data to an external server when a higher-privileged user views it, bypassing the external content restriction through a Cascading Style Sheets (CSS) injection.<br><br>The Trusted Domains security check does not fully validate inline style attribute values, which can allow for outbound requests to untrusted domains and credential exfiltration when a victim views a crafted dashboard.

Affected products

Splunk Enterprise: from 9.3.0 before 9.3.13; from 9.4.0 before 9.4.12; from 10.0.0 before 10.0.7; from 10.2.0 before 10.2.4 — fixed in 10.0.7, 10.2.4, 9.3.13, 9.4.12
Splunk Cloud Platform: from 9.3.2411 before 9.3.2411.132; from 10.1.2507 before 10.1.2507.23; from 10.2.2510 before 10.2.2510.15; from 10.3.2512 before 10.3.2512.13 — fixed in 10.1.2507.23, 10.2.2510.15, 10.3.2512.13, 9.3.2411.132

How to fix

Upgrade to a fixed version: Splunk Enterprise 10.0.7, 10.2.4, 9.3.13, 9.4.12; Splunk Cloud Platform 10.1.2507.23, 10.2.2510.15, 10.3.2512.13, 9.3.2411.132. Check the vendor advisory for mitigations.

References

https://advisory.splunk.com/advisories/SVD-2026-0604

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