In Splunk Enterprise versions below 10.4.3 and 10.2.7, an unauthenticated user with network access to the Patroni Representational State Transfer (REST) Application Programming Interface (API) on a search head cluster member could execute attacker-controlled operating-system commands. The vulnerability is possible because this interface does not require authentication for critical configuration operations. For more information see Sidecar configuration settings (https://help.splunk.com/en/data-management/splunk-enterprise-admin-manual/10.2/splunk-sidecars/sidecar-configuration-settings) in the Splunk documentation.
Splunk Enterprise versions 10.0.x and 9.4.x are not affected.
Turn off the PostgreSQL sidecar by setting disabled = true in the [postgres] stanza of $SPLUNK_HOME/etc/system/local/server.conf if you do not use Edge Processor, OpAmp, or SPL2 data pipelines. Restart Splunk Enterprise to apply the change. For more information see Sidecar configuration settings and server.conf in the Splunk documentation.
Upgrade Splunk Enterprise to versions 10.4.3, 10.2.7, 10.0.10, and 9.4.15, or higher.