CVE-2026-20139 | Client-Side Denial of Service (DoS) through ''/splunkd/__raw/services/authentication/users/username'' REST API endpoint in Splunk Enterprise

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.

Published: 2026-02-18 Last update: 2026-02-20 Assigner: [email protected] Source: [email protected]

NVD Status：Analyzed，CVE State: published

View at NVD, CVE.org, EUVD

Conclusion & alert: CVE-2026-20139 is rated Low Risk (22.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-20139

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-15	0.04%	0.05%	+0.01%
2	2026-02-19	—	0.04%	—

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-20139

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
4.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	2.8	1.4	[email protected]

Weakness enumeration for CVE-2026-20139

CWE-400 MITRE ↗

Affected software / configurations for CVE-2026-20139

Vendor	Product	Version	Raw CPE
splunk	splunk	>= 9.2.0, < 9.2.12	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	>= 9.3.0, < 9.3.9	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	>= 9.4.0, < 9.4.8	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	>= 10.0.0, < 10.0.2	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk_cloud_platform	>= 9.3.2411, < 9.3.2411.121	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
splunk	splunk_cloud_platform	>= 10.0.2503, < 10.0.2503.9	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
splunk	splunk_cloud_platform	>= 10.1.2507, < 10.1.2507.8	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
splunk	splunk_cloud_platform	>= 10.2.2510, < 10.2.2510.3	cpe:2.3:a:splunk:splunk_cloud_platform::::::::

References for CVE-2026-20139

URL	Tags
https://advisory.splunk.com/advisories/SVD-2026-0204	Vendor Advisory

cvelogic Threat Intelligence