What’s Vulnerable › Vulnerabilities
CVE-2026-20139: Client-Side Denial of Service (DoS) through ''/splunkd/__raw/services/authentication/users/username'' REST API endpoint in Splunk Enterprise
- Severity: medium (CVSS 4.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 5.7% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-02-18 · updated 2026-06-17
- Weakness: CWE-400
Description
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 Enterprise: from 9.2.0 before 9.2.12; from 9.3.0 before 9.3.9; from 9.4.0 before 9.4.8; from 10.0.0 before 10.0.2 — fixed in 10.0.2, 9.2.12, 9.3.9, 9.4.8
- Splunk Cloud Platform: from 9.3.2411 before 9.3.2411.121; from 10.0.2503 before 10.0.2503.9; from 10.1.2507 before 10.1.2507.8; from 10.2.2510 before 10.2.2510.3 — fixed in 10.0.2503.9, 10.1.2507.8, 10.2.2510.3, 9.3.2411.121
How to fix
Upgrade to a fixed version: Splunk Enterprise 10.0.2, 9.2.12, 9.3.9, 9.4.8; Splunk Cloud Platform 10.0.2503.9, 10.1.2507.8, 10.2.2510.3, 9.3.2411.121. Check the vendor advisory for mitigations.
References
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