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

> An unauthenticated attacker can trick users into visiting malicious external sites via crafted login URLs in Splunk Enterprise.

- **Severity:** Low 3.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Nov 2025
- **Updated:** 12 Nov 2025
- **Also known as:** GHSA-r9qj-q2g9-r74r

## What is CVE-2025-20378?

CVE-2025-20378 is a low-severity vulnerability in Splunk Splunk, published on 12 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2025-20378?

It affects 2 products.


Products: Splunk Splunk, Splunk Splunk Cloud Platform.

## How do I fix CVE-2025-20378?

No fix has been published for CVE-2025-20378 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-20378 being exploited?

There is no known exploitation of CVE-2025-20378 in the wild and no public exploit code.

## Other vulnerabilities in Splunk Splunk

- [CVE-2026-20253](https://insights.sbomify.com/CVE-2026-20253/): Splunk Enterprise Missing Authentication for Critical Function (critical 9.8, exploited in the wild)
- [CVE-2026-76268](https://insights.sbomify.com/CVE-2026-76268/): Missing Authentication for Critical Function in the Patroni REST API in Splunk Enterprise (critical 9.8)
- [CVE-2026-76284](https://insights.sbomify.com/CVE-2026-76284/): Improper Neutralization in Splunk Enterprise (critical 9.8)
- [CVE-2026-76285](https://insights.sbomify.com/CVE-2026-76285/): Improper Adherence to Coding Standards in Splunk Enterprise (critical 9.8)
- [CVE-2017-17067](https://insights.sbomify.com/CVE-2017-17067/): Auth bypass in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-20378 and fix it if it is affected.

What it is: CVE-2025-20378 is a low-severity vulnerability in Splunk Splunk, published on 12 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-20378 in the wild and no public exploit code.

Affected product: Splunk Splunk. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-20378/ (Markdown: https://insights.sbomify.com/CVE-2025-20378/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-20378
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-20378
- OSV: https://osv.dev/vulnerability/CVE-2025-20378

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-20378/
Summaries are generated and may contain mistakes; the official description above is the record.