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Fencer Vulns
medium 4.3

CVE-2026-20139 json

Client-Side Denial of Service (DoS) through ''/splunkd/__raw/services/authentication/users/username'' REST API endpoint in Splunk Enterprise

published 2026-02-18 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-8197

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
5.7%
EPSS 5.7% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

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.

Patch / fix

  • Splunk Splunk Enterprise 9.2.12, 9.3.9, 9.4.8, 10.0.2
  • Splunk Splunk Cloud Platform 9.3.2411.121, 10.0.2503.9, 10.1.2507.8, 10.2.2510.3

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

5.68% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected products

  • Splunk Splunk Enterprise
  • Splunk Splunk Cloud Platform

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.