CVE-2026-20139 Denial of service in Splunk Cloud Platform
A low-privileged user can cause client-side denial of service in Splunk Web by crafting malicious payloads in user profile parameters.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-20139?
CVE-2026-20139 is a medium-severity denial of service vulnerability in Splunk Splunk, published on 18 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-400
Which versions are affected by CVE-2026-20139?
It affects 2 products.
Products include Splunk Splunk, Splunk Splunk Cloud Platform.
How do I fix CVE-2026-20139?
No fix has been published for CVE-2026-20139 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-20139 being exploited?
There is no known exploitation of CVE-2026-20139 in the wild and no public exploit code.
Other vulnerabilities in Splunk Splunk
- CVE-2026-20253 Splunk Enterprise Missing Authentication for Critical Function
- CVE-2026-76268 Missing Authentication for Critical Function in the Patroni REST API in Splunk Enterprise
- CVE-2026-76284 Improper Neutralization in Splunk Enterprise
- CVE-2026-76285 Improper Adherence to Coding Standards in Splunk Enterprise
- CVE-2017-17067 Auth bypass in n/a
Sources
Also known as GHSA-4vmx-r9fj-4cm5.