# CVE-2026-20251: Remote Code Execution through Deserialization of Untrusted Data in Splunk Secure Gateway

> A low-privileged user can achieve remote code execution in Splunk Secure Gateway via unsafe deserialization of KV Store data using jsonpickle.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Jun 2026
- **Updated:** 11 Jun 2026
- **Also known as:** GHSA-3crw-7xg9-fpxg

## What is CVE-2026-20251?

CVE-2026-20251 is a high-severity unsafe deserialization vulnerability in Splunk Splunk, published on 10 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, Splunk Cloud Platform versions below 10.3.2512.12, 10.2.2510.14, 10.1.2507.22, and 9.3.2411.132, and Splunk Secure Gateway versions below 3.10.6, 3.9.20, and 3.8.67, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could perform a Remote Code Execution (RCE) through the Splunk Secure Gateway app.<br><br>The Remote Code Execution is possible because of unsafe deserialization of App Key Value Store (KV Store) data through the ‘jsonpickle’ Python library, which reconstructs arbitrary Python objects from specially crafted JavaScript Object Notation (JSON) without adequate validation.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-20251?

It affects 3 products.


Products: Splunk Splunk, Splunk Splunk Cloud Platform, Splunk Splunk Secure Gateway.

## How do I fix CVE-2026-20251?

No fix has been published for CVE-2026-20251 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20251 being exploited?

There is no known exploitation of CVE-2026-20251 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-20251 — Splunk Secure Gateway jsonpickle deserialization RCE (CVSS 8.8) | ReactiveZero Security Research (github_poc): https://github.com/reactivezero/CVE-2026-20251

## 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-2026-20251 and fix it if it is affected.

What it is: CVE-2026-20251 is a high-severity unsafe deserialization vulnerability in Splunk Splunk, published on 10 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-20251 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-2026-20251/ (Markdown: https://insights.sbomify.com/CVE-2026-20251/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20251
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20251
- OSV: https://osv.dev/vulnerability/CVE-2026-20251

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20251/
Summaries are generated and may contain mistakes; the official description above is the record.