CVE-2025-20378

Description

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.

CVSS v3.1 Score

3.1

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Weakness Type (CWE)

CWE-601 CWE-601

Affected Products

Vendor	Product	Versions
splunk	splunk	9.2.0 — 9.2.9
splunk	splunk	9.3.0 — 9.3.7
splunk	splunk	9.4.0 — 9.4.5
splunk	splunk	All
splunk	splunk_cloud_platform	9.3.2408 — 9.3.2408.121
splunk	splunk_cloud_platform	9.3.2411 — 9.3.2411.111
splunk	splunk_cloud_platform	10.0.2503 — 10.0.2503.5

References

Advisories & Patches

https://advisory.splunk.com/advisories/SVD-2025-1101

Frequently Asked Questions

What is CVE-2025-20378? +

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. It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2025-20378? +

CVE-2025-20378 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

What products are affected by CVE-2025-20378? +

CVE-2025-20378 affects products from splunk, specifically: splunk, splunk_cloud_platform. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-20378? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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