CVE-2026-76290 in Splunk
Summary
by MITRE • 10/22/2026
In Splunk Enterprise versions below 10.4.4, 10.2.8, and 10.0.11, an unauthenticated user could send repeated requests to the Edge Processor package download endpoint in the Splunk Pipeline Builders app. The requests could cause the Splunk daemon to consume excessive system resources and potentially stop responding. The vulnerability is possible because the endpoint accepts package download requests without authentication and reads and base64-encodes the complete package in memory for each request. After upgrading, prepare all existing Edge Processor instances, turn on authentication for Edge Processor package downloads, and restart Splunk Enterprise. For more information, see Enable authentication for Edge Processor package downloads (https://help.splunk.com/en/data-management/process-data-at-the-edge/use-edge-processors-for-splunk-enterprise/10.4/administer-edge-processors/enable-authentication-for-edge-processor-package-downloads).
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Analysis
by VulDB Data Team • 10/22/2026
The identified vulnerability in Splunk Enterprise versions prior to 10.4.4, 10.2.8, and 10.0.11 represents a critical resource exhaustion flaw within the Edge Processor package download endpoint of the Splunk Pipeline Builders application. This security issue stems from an architectural oversight where the specific API endpoint responsible for handling package downloads operates without requiring any form of authentication or access control verification. Consequently, any unauthenticated actor on the network can interact with this service directly, bypassing standard enterprise security boundaries that would typically restrict such administrative functions to authorized personnel only.
The technical mechanism driving this vulnerability involves the server-side processing logic applied to each incoming request. When a client requests an Edge Processor package, the Splunk daemon retrieves the complete file content and performs base64 encoding on it entirely within system memory before sending the response back to the requester. This design choice creates a significant performance bottleneck because base64 encoding increases data size by approximately thirty-three percent while simultaneously consuming substantial CPU cycles for character conversion. More critically, allocating large blocks of RAM to hold these encoded payloads in memory without proper limits or streaming mechanisms leads to rapid resource depletion under load.
An attacker can exploit this flaw through a simple denial-of-service attack vector by sending repeated requests at high frequency. Since each request triggers the full read and encode cycle in memory, an automated script can quickly exhaust available system resources such as RAM and CPU capacity. This excessive consumption causes the Splunk daemon to become unresponsive or crash entirely, resulting in a complete service outage for users relying on the platform for data ingestion, indexing, and analysis. The impact is particularly severe because it affects core infrastructure components that are often central to an organization's security operations center workflows.
From a classification perspective, this vulnerability aligns with CWE-787: Out-of-bounds Read or Write in terms of memory management inefficiencies leading to instability, but more accurately fits CWE-400: Uncontrolled Resource Consumption which leads to Denial of Service. In the context of the MITRE ATT&CK framework, this behavior is consistent with T1499: Endpoint Denial of Service, specifically under techniques that involve resource exhaustion through application layer attacks rather than network flooding. The lack of authentication also relates to CWE-287: Improper Authentication, as the system fails to verify the identity of the requester before performing expensive computational tasks.
To mitigate this risk and restore secure operations, administrators must upgrade Splunk Enterprise to version 10.4.4 or later, which includes patches addressing these resource management issues. Following the upgrade, it is imperative to prepare all existing Edge Processor instances for the new security model by explicitly enabling authentication for Edge Processor package downloads as documented in official Splunk administration guides. This configuration change ensures that only authenticated and authorized users can trigger package download operations, thereby eliminating the attack surface available to unauthenticated actors. Finally, a restart of the Splunk Enterprise service is required to apply these configuration changes effectively and ensure the daemon operates with the updated security controls active.