# CVE-2026-20253: Splunk Enterprise Missing Authentication for Critical Function

> Unauthenticated attackers can create or truncate arbitrary files via an unprotected PostgreSQL sidecar endpoint in Splunk Enterprise.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 18 Jun 2026 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jun 2026
- **Updated:** 19 Jun 2026
- **Also known as:** GHSA-xgm5-jh99-wc4v

## What is CVE-2026-20253?

CVE-2026-20253 is a critical missing authorization vulnerability in Splunk Splunk, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials. Splunk Enterprise versions 9.4 and earlier are not affected. If you cannot immediately upgrade to a fixed version, you can mitigate this vulnerability by disabling the PostgreSQL sidecar service.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-20253?

It affects 1 product.


Products: Splunk Splunk.

## How do I fix CVE-2026-20253?

No fix has been published for CVE-2026-20253 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 21 Jun 2026.

## Is CVE-2026-20253 being exploited?

Yes. Attackers have exploited CVE-2026-20253 in the wild since at least 18 Jun 2026.

Public exploit code:

- https://github.com/watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253 (github_poc): https://github.com/watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253
- CVE-2026-20253 (github_poc): https://github.com/0xredash/CVE-2026-20253
- CVE-2026-20253 - Splunk Enterprise (github_poc): https://github.com/HORKimhab/CVE-2026-20253
- PoC de CVE-2026-20253: RCE pre-autenticacion en Splunk Enterprise. (github_poc): https://github.com/fevar54/CVE-2026-20253-Splunk-Enterprise-Pre-Auth-RCE-
- POC for CVE-2026-20253 (github_poc): https://github.com/pssec-io/CVE-2026-20253
- https://github.com/Het-Kalariya/CVE-2026-20253 (github_poc): https://github.com/Het-Kalariya/CVE-2026-20253

## Other vulnerabilities in Splunk Splunk

- [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)
- [CVE-2016-10126](https://insights.sbomify.com/CVE-2016-10126/): Information disclosure in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20253 and fix it if it is affected.

What it is: CVE-2026-20253 is a critical missing authorization vulnerability in Splunk Splunk, published on 10 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2026-20253 in the wild since at least 18 Jun 2026.

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-2026-20253/ (Markdown: https://insights.sbomify.com/CVE-2026-20253/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20253
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20253
- OSV: https://osv.dev/vulnerability/CVE-2026-20253

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20253/
Summaries are generated and may contain mistakes; the official description above is the record.