CVE-2026-20257

Improper Input Validation through Classic Dashboard CSS in Splunk Enterprise

Severity
Medium 5.7
CVSS 3.1
Exploited
Not listed
EPSS
0.003
21.5th percentile
Discovered by
Not disclosed
Published
Jun 10, 2026
Assigned by cisco

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 classic dashboard that exfiltrates sensitive data from the browser of a higher-privileged user who views it. The exfiltration is possible because classic dashboard panels do not fully validate style attribute values, which can allow for requests to reach external domains outside the configured Trusted Domains List. The vulnerability requires the attacker to phish the victim by tricking them into initiating a request within their browser. The low-privileged user should not be able to exploit the vulnerability at will.

Weakness: CWE-20

Affected products

Vendor Product Category Matched by

No product mapping yet — this CVE is pending taxonomy review.

Vendor-reported affected versions (2)
  • Splunk · Splunk Enterprise
  • Splunk · Splunk Cloud Platform

Credit

Tony Tong (tongster)