# CVE-2026-20202: Improper Input Validation during User Account Creation in Splunk Enterprise


- **Severity:** Medium 6.6 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 15 Apr 2026
- **Updated:** 16 Apr 2026
- **Also known as:** GHSA-p3vg-7hj9-6f24

## What is CVE-2026-20202?

CVE-2026-20202 is a medium-severity vulnerability in Splunk Splunk, published on 15 Apr 2026. 

### Official description

In Splunk Enterprise versions below 10.2.2, 10.0.5, 9.4.10, and 9.3.11, and Splunk Cloud Platform versions below 10.4.2603.0, 10.3.2512.6, 10.2.2510.10, 10.1.2507.20, 10.0.2503.13, and 9.3.2411.127, a user who holds a role that contains the high-privilege capability `edit_user`could create a specially crafted username that includes a null byte or a non-UTF-8 percent-encoded byte due to improper input validation.<br><br>This could lead to inconsistent conversion of usernames into a proper format for storage and account management inconsistencies, such as being unable to edit or delete affected users.

Weakness: CWE-176 (Improper Handling of Unicode Encoding)

## Which versions are affected by CVE-2026-20202?

It affects 2 products.


Products: Splunk Splunk, Splunk Splunk Cloud Platform.

## How do I fix CVE-2026-20202?

No fix has been published for CVE-2026-20202 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20202 being exploited?

There is no known exploitation of CVE-2026-20202 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-2026-20202 and fix it if it is affected.

What it is: CVE-2026-20202 is a medium-severity vulnerability in Splunk Splunk, published on 15 Apr 2026. 
Exploitation: There is no known exploitation of CVE-2026-20202 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-2026-20202/ (Markdown: https://insights.sbomify.com/CVE-2026-20202/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20202
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20202
- OSV: https://osv.dev/vulnerability/CVE-2026-20202

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20202/
Summaries are generated and may contain mistakes; the official description above is the record.