CVE-2026-20253criticalunder attackCWE-306

CVE-2026-20253: critical vulnerability in Splunk Enterprise

Unauthenticated Arbitrary File Creation and Truncation in a PostgreSQL Sidecar Service Endpoint in Splunk Enterprise

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100Vexday Risk Score

Patch now. It under exploitation confirmed by CISA, has an official Brazilian government alert and has a working public exploit.

ssvc Actcvss 9.8epss 97%
from disclosure to weapon2 days
Published on NVDJun 10
1st PoC+2d
CISA KEV+8d
Official alert in Brazil

Brazil's federal government published an alert, recommendation or bulletin that cites this vulnerability.

Source: CTIR Gov (GSI) and CISC Gov.br, under the CC BY-ND 3.0 license.
Action required by CISAfederal deadline: 2026-06-21

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.

In short

An attacker without login credentials can create or delete files on a Splunk server by accessing an unprotected PostgreSQL service. This is critical because it allows unauthorized modification of system files that could crash the system or expose sensitive data.

Technical detail

CWE-306: Missing Authentication Check. An unauthenticated attacker can invoke file creation and truncation operations on the PostgreSQL sidecar service endpoint in affected Splunk Enterprise versions (10.2.x <10.2.4, 10.x <10.0.7) through network access, resulting in arbitrary file manipulation with system-level impact.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Splunk · Splunk Enterprise
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