Actively exploited · Published Jun 10, 2026 · Assigned by cisco
CVE-2026-20253Unauthenticated Arbitrary File Creation and Truncation in a PostgreSQL Sidecar Service Endpoint in Splunk Enterprise
Critical 9.8 Exploited
In plain English
A critical-severity missing authentication in Splunk Enterprise from Splunk. Attackers are actively exploiting it in the wild (listed by CISA on June 18, 2026). The chance it is exploited in the next 30 days is estimated at 96.9% (higher than 99.9% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. 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 guidance
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.
Federal agencies must remediate by Jun 21, 2026.
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Splunk | Splunk Enterprise | 10.2 – before 10.2.410.0 – before 10.0.7 |
Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H