CVE-2025-20378 | Open Redirect on Web Login endpoint in Splunk Enterprise

In Splunk Enterprise versions below 10.0.1, 9.4.5, 9.3.7, 9.2.9, and Splunk Cloud Platform versions below 10.0.2503.5, 9.3.2411.111, and 9.3.2408.121, an unauthenticated attacker could craft a malicious URL using the `return_to` parameter of the Splunk Web login endpoint. When an authenticated user visits the malicious URL, it could cause an unvalidated redirect to an external malicious site. To be successful, the attacker has to trick the victim into initiating a request from their browser. The unauthenticated attacker should not be able to exploit the vulnerability at will.

Published: 2025-11-12 Last update: 2025-12-03 Assigner: [email protected] Source: [email protected]

NVD Status：Analyzed，CVE State: published

View at NVD, CVE.org, EUVD

Conclusion & alert: CVE-2025-20378 is rated Low Risk (18.3/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.05%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

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-2025-20378

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	2026-04-22	0.03%	0.05%	+0.02%
2	2026-04-10	0.06%	0.03%	-0.02%
3	2026-01-19	—	0.06%	—

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-20378

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
3.1	3.1	LOW	`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N` 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:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	1.6	1.4	[email protected]
6.1	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N` 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:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	2.8	2.7	[email protected]

Weakness enumeration for CVE-2025-20378

CWE-601 MITRE ↗

Affected software / configurations for CVE-2025-20378

Vendor	Product	Version	Raw CPE
splunk	splunk	>= 9.2.0, < 9.2.9	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	>= 9.3.0, < 9.3.7	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	>= 9.4.0, < 9.4.5	cpe:2.3:a:splunk:splunk:::::enterprise:::*
splunk	splunk	10.0.0	cpe:2.3:a:splunk:splunk:10.0.0::::enterprise:::
splunk	splunk_cloud_platform	>= 9.3.2408, < 9.3.2408.121	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
splunk	splunk_cloud_platform	>= 9.3.2411, < 9.3.2411.111	cpe:2.3:a:splunk:splunk_cloud_platform::::::::
splunk	splunk_cloud_platform	>= 10.0.2503, < 10.0.2503.5	cpe:2.3:a:splunk:splunk_cloud_platform::::::::

References for CVE-2025-20378

URL	Tags
https://advisory.splunk.com/advisories/SVD-2025-1101	Vendor Advisory

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