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

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2026-06-18. EPSS: 96.9% chance of exploitation in the next 30 days.

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

• Splunk Splunk: from 10.0.0, before 10.0.7 (fixed in 10.0.7); from 10.2.0, before 10.2.4 (fixed in 10.2.4)

Published 2026-06-10. Last modified 2026-07-23.