CVE-2026-76400: Denial of Service (DoS) through the REST API in Splunk Connect for Kafka

What it is

In Splunk Connect for Kafka versions below 2.2.7, an unauthenticated user who can reach the Kafka Connect Representational State Transfer (REST) API and influence responses from a Hypertext Transfer Protocol (HTTP) Event Collector endpoint in Splunk Enterprise could cause the connector to retry failed event batches until event delivery stops. The vulnerability is possible because HTTP Event Collector delivery retry handling uses an unbounded default for failed batches instead of a finite retry limit. For more information see Install Splunk Connect for Kafka (https://help.splunk.com/en/data-management/integrate-data-with-add-ons/splunk-connect-for-kafka/2.2/install/install-splunk-connect-for-kafka), Data ingestion parameters for Splunk Connect for Kafka (https://help.splunk.com/en/data-management/integrate-data-with-add-ons/splunk-connect-for-kafka/2.2/overview/data-ingestion-parameters-for-splunk-connect-for-kafka), and Set up and use HTTP Event Collector with configuration files (https://help.splunk.com/en/splunk-enterprise/get-data-in/get-started-with-getting-data-in/9.4/get-data-with-http-event-collector/set-up-and-use-http-event-collector-with-configuration-files) in the Splunk documentation.

Workarounds

Restrict access to the Kafka Connect Representational State Transfer (REST) API to trusted administrative hosts and networks. Set a finite HTTP Event Collector retry limit in the connector configuration. For more information see [Data ingestion parameters for Splunk Connect for Kafka](https://help.splunk.com/en/data-management/integrate-data-with-add-ons/splunk-connect-for-kafka/2.2/overview/data-ingestion-parameters-for-splunk-connect-for-kafka) in the Splunk documentation.