Description

Splunk administrators operating in Windows environments are urged to update their deployments immediately after the discovery of two high-severity vulnerabilities impacting both Splunk Enterprise and the Universal Forwarder. Tracked as CVE-2025-20386 and CVE-2025-20387, both issues carry a CVSS score of 8.0, reflecting the significant security risk they pose. The vulnerabilities originate from incorrect file permissions applied during installation or upgrade processes. Splunk’s advisory explains that affected versions may assign overly permissive access rights to the Windows installation directories. As a result, critical folders—such as C:\Program Files\Splunk and C:\Program Files\SplunkUniversalForwarder—may be accessible to non-administrative users. These directories typically contain configuration files, logs, and operational components that should only be handled by administrators or SYSTEM-level accounts. Although the flaw does not constitute a traditional remote code execution vulnerability, it substantially weakens local security controls. A low-privileged user who already has access to the host could read sensitive files or potentially modify components within the Splunk directory, enabling further compromise or privilege escalation. Systems are at risk if they are running Splunk Enterprise or the Universal Forwarder on Windows versions earlier than 10.0.2, 9.4.6, 9.3.8, or 9.2.10. Splunk has released updated versions that correct the improper permissions, and the primary remediation recommendation is to upgrade to these fixed releases or newer. For organizations unable to apply patches immediately, Splunk has provided a temporary workaround. Administrators can manually correct permissions using the Windows icacls command to restrict access until a full upgrade can be completed.