Splunk Enterprise/Cloud Platform REST API Endpoint username realname/tz/email resource consumption

Summaryinfo

A vulnerability classified as problematic was found in Splunk Enterprise and Cloud Platform. The impacted element is an unknown function of the file /splunkd/__raw/services/authentication/users/username of the component REST API Endpoint. The manipulation of the argument realname/tz/email results in resource consumption. This vulnerability is cataloged as CVE-2026-20139. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Splunk Enterprise and Cloud Platform (version unknown). Affected is an unknown function of the file /splunkd/__raw/services/authentication/users/username of the component REST API Endpoint. The manipulation of the argument realname/tz/email with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at advisory.splunk.com. This vulnerability is traded as CVE-2026-20139 since 10/08/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 299411 (Splunk Enterprise 9.2.0 < 9.2.12, 9.3.0 < 9.3.9, 9.4.0 < 9.4.8, 10.0.0 < 10.0.2 (SVD-2026-0204)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (299411) and CERT Bund (WID-SEC-2026-0457). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Splunk Splunk Enterprise

Productinfo

Type

• Log Management Software

Vendor

• Splunk

Name

• Cloud Platform
• Enterprise

License

• commercial

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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