---
title: "CVE-2026-20253: Splunk Enterprise Missing Authentication for Critical Function Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-20253/
description: "CVE-2026-20253 (Splunk Enterprise): Exploited in the wild (CISA KEV). In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-10
date_modified: 2026-06-19
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-20253"
kev: true
cvss: 9.8
epss: 0.96939
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Splunk Enterprise. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-06-18, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-06-21 ; treat that as the outer limit, not the target.
- EPSS 96.9% , percentile 99.9: FIRST’s model estimates a 96.9% chance of exploitation activity in the next 30 days, higher than 99.9% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.

## What it is

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.

## Affected products (CVE record)

- Splunk Splunk Enterprise: 10.2 < 10.2.4, 10.0 < 10.0.7

## Severity

- cisco CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2026-06-18; federal due date 2026-06-21. Known ransomware use: Unknown.
- CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 96.94% probability of exploitation activity in the next 30 days; percentile 99.9.

## Sources

- [Listed in CISA KEV notes (advisory.splunk.com)](https://advisory.splunk.com/advisories/SVD-2026-0603)
- [CVE.org record CVE-2026-20253](https://www.cve.org/CVERecord?id=CVE-2026-20253)
- [NVD entry CVE-2026-20253](https://nvd.nist.gov/vuln/detail/CVE-2026-20253)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20253)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)
- [labs.watchtowr.com](https://labs.watchtowr.com/why-use-app-level-auth-when-every-database-has-auth-splunk-enterprise-cve-2026-20253-pre-auth-rce/)

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Source page: https://erroneo.us/security/cve/CVE-2026-20253/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt