CVE-2025-20371 is a server-side request forgery (SSRF) vulnerability identified in multiple versions of Splunk Enterprise and Splunk Cloud Platform. The vulnerability arises because the web server component accepts URL requests from upstream components and retrieves their contents without sufficient validation to ensure the request targets an expected or authorized destination. This lack of validation enables an unauthenticated attacker to craft malicious requests that cause the server to perform unauthorized REST API calls. These calls can be executed with the privileges of a high-privileged authenticated user, effectively allowing the attacker to bypass authentication and authorization controls. The vulnerability affects Splunk Enterprise versions below 10.0.1, 9.4.4, 9.3.6, and 9.2.8, as well as Splunk Cloud Platform versions below 9.3.2411.109, 9.3.2408.119, and 9.2.2406.122. The CVSS v3.1 score of 7.5 reflects a high severity, with network attack vector, high impact on confidentiality, integrity, and availability, and requiring user interaction but no privileges. While no public exploits have been reported, the potential for an attacker to perform REST API calls on behalf of privileged users poses significant risk, including data exfiltration, system manipulation, and service disruption. The vulnerability was reserved in October 2024 and published in October 2025, indicating a recent disclosure. The absence of patches in the provided data suggests organizations must verify and apply vendor updates promptly. The attack complexity is high due to the need for user interaction, but the lack of required privileges and network accessibility increases the threat surface. This vulnerability is particularly critical in environments where Splunk is used for security monitoring and operational intelligence, as compromise could undermine detection capabilities and system integrity.

For European organizations, the impact of CVE-2025-20371 can be severe. Splunk is widely used across Europe for security information and event management (SIEM), operational monitoring, and compliance reporting. Exploitation could allow attackers to perform unauthorized REST API calls, potentially leading to unauthorized data access, manipulation of logs or configurations, and disruption of monitoring services. This undermines the confidentiality and integrity of critical security data and could delay incident detection and response. Organizations in sectors such as finance, energy, telecommunications, and government are particularly at risk due to their reliance on Splunk for security operations. The vulnerability could also facilitate lateral movement within networks if attackers leverage Splunk’s privileged access. Given the high CVSS score and the unauthenticated nature of the attack, the threat is significant. The lack of known exploits in the wild provides a window for proactive defense, but the risk of targeted attacks exploiting this vulnerability remains high. Failure to patch could lead to regulatory non-compliance under GDPR and other European data protection laws if data breaches occur.

European organizations should immediately verify their Splunk Enterprise and Cloud Platform versions and upgrade to the patched releases: 10.0.1 or later for Splunk Enterprise and the corresponding patched versions for Splunk Cloud Platform. In the absence of immediate patching, organizations should implement strict network segmentation to limit access to Splunk management interfaces and REST APIs, restricting them to trusted internal networks only. Deploy web application firewalls (WAFs) with rules to detect and block SSRF patterns targeting Splunk endpoints. Monitor Splunk REST API logs for unusual or unauthorized activity, especially requests originating from unexpected sources or with suspicious parameters. Employ multi-factor authentication and least privilege principles for Splunk users to reduce the impact of potential impersonation. Conduct regular security assessments and penetration testing focused on SSRF and API abuse scenarios. Finally, maintain up-to-date threat intelligence feeds to detect emerging exploit attempts and coordinate with Splunk support for timely updates and advisories.