CVE-2026-20139: Splunk

Medium severity, CVSS 4.3. EPSS: 5.2% chance of exploitation in the next 30 days.

In Splunk Enterprise versions below 10.2.0, 10.0.2, 9.4.8, 9.3.9, and 9.2.12, and Splunk Cloud Platform versions below 10.2.2510.3, 10.1.2507.8, 10.0.2503.9, and 9.3.2411.121, a low-privileged user that does not hold the "admin" or "power" Splunk roles could craft a malicious payload into the `realname`, `tz`, or `email` parameters of the `/splunkd/__raw/services/authentication/users/username` REST API endpoint when they change a password. This could potentially lead to a client‑side denial‑of‑service (DoS). The malicious payload might significantly slow page load times or render Splunk Web temporarily unresponsive.

Affected products

• Splunk Splunk: from 9.2.0, before 9.2.12 (fixed in 9.2.12); from 9.3.0, before 9.3.9 (fixed in 9.3.9); from 9.4.0, before 9.4.8 (fixed in 9.4.8); from 10.0.0, before 10.0.2 (fixed in 10.0.2)
• Splunk Splunk Cloud Platform: from 9.3.2411, before 9.3.2411.121 (fixed in 9.3.2411.121); from 10.0.2503, before 10.0.2503.9 (fixed in 10.0.2503.9); from 10.1.2507, before 10.1.2507.8 (fixed in 10.1.2507.8); from 10.2.2510, before 10.2.2510.3 (fixed in 10.2.2510.3)

Published 2026-02-18. Last modified 2026-06-17.