CVE-2025-20370 is a medium-severity vulnerability affecting multiple versions of Splunk Enterprise (below 10.0.1, 9.4.4, 9.3.6, and 9.2.8) and Splunk Cloud Platform (below 9.3.2411.108, 9.3.2408.118, and 9.2.2406.123). The flaw arises from improper control over the allocation and maintenance of a limited resource related to LDAP bind requests. Specifically, a user with a role containing the high-privilege capability 'change_authentication' can send multiple LDAP bind requests to a specific internal endpoint. This causes excessive CPU consumption on the Splunk server, potentially leading to a denial of service (DoS) condition that persists until the affected Splunk instance is restarted. The vulnerability does not impact confidentiality or integrity but affects availability by exhausting server resources. Exploitation requires a privileged user account (with 'change_authentication' capability), no user interaction is needed beyond that, and the attack can be performed remotely over the network. The CVSS 3.1 base score is 4.9 (medium), reflecting the requirement for high privileges and the lack of confidentiality or integrity impact. No known exploits in the wild have been reported yet. The vulnerability highlights the risk of resource exhaustion through repeated LDAP bind requests, which can disrupt critical log management and security monitoring functions provided by Splunk Enterprise and Cloud Platform. The issue can be mitigated by upgrading to patched versions beyond the affected releases.

For European organizations, the impact of this vulnerability can be significant, especially for those relying heavily on Splunk Enterprise or Splunk Cloud Platform for security information and event management (SIEM), compliance monitoring, and operational intelligence. A successful DoS attack could disrupt log collection, analysis, and alerting capabilities, delaying detection of other security incidents and impacting incident response. This is particularly critical for sectors with stringent regulatory requirements such as finance, healthcare, energy, and government agencies across Europe. The requirement for a high-privilege user to exploit the vulnerability somewhat limits the attack surface; however, insider threats or compromised privileged accounts could still trigger the DoS condition. The disruption of Splunk services could also affect business continuity and operational efficiency. Given the central role of Splunk in aggregating and analyzing security logs, availability issues could indirectly increase the risk of undetected cyberattacks or compliance violations.

1. Upgrade affected Splunk Enterprise and Splunk Cloud Platform instances to versions 10.0.1 or later, 9.4.4 or later, 9.3.6 or later, and 9.2.8 or later as applicable, where the vulnerability is patched. 2. Review and restrict the assignment of the 'change_authentication' capability to only trusted, essential users to minimize the risk of exploitation. 3. Implement strict monitoring and alerting on unusual LDAP bind request patterns or spikes in CPU usage on Splunk servers to detect potential exploitation attempts early. 4. Employ network segmentation and access controls to limit which users and systems can communicate with the internal LDAP endpoints of Splunk. 5. Conduct regular audits of privileged accounts and their activities to detect misuse or compromise. 6. Consider deploying rate limiting or throttling mechanisms on LDAP bind requests if supported by the environment to prevent resource exhaustion. 7. Maintain up-to-date incident response plans that include scenarios involving Splunk service disruptions.