CVE-2026-20142 is a vulnerability affecting multiple versions of Splunk Enterprise prior to 10.2.0, 10.0.2, 9.4.7, 9.3.9, and 9.2.11. The issue arises in Splunk Search Head Cluster (SHC) deployments where users with roles permitting access to the Splunk _internal index can view sensitive information logged in plaintext. Specifically, the RSA accessKey value from the authentication.conf configuration file is exposed in these logs. This key is critical for authentication processes and its exposure can enable attackers to impersonate legitimate users or escalate privileges within the Splunk environment. The vulnerability is classified under CWE-532 (Information Exposure Through Log Files), highlighting improper handling of sensitive data in logs. The CVSS 3.1 base score is 6.8, reflecting a medium severity with the vector indicating the attack requires authenticated access (PR:H), no user interaction (UI:N), and has a network attack vector (AV:A). The impact affects confidentiality, integrity, and availability, as the exposed key could be used to compromise system security and data integrity. No public exploits have been reported yet, but the presence of sensitive keys in logs is a critical security misconfiguration. The vulnerability affects multiple widely used versions of Splunk Enterprise, a popular platform for security information and event management (SIEM), log aggregation, and operational intelligence. Organizations relying on these versions in SHC deployments are at risk of internal threat actors or compromised accounts leveraging this exposure to gain unauthorized access or disrupt services.

For European organizations, the exposure of the RSA accessKey in Splunk Enterprise logs can lead to significant security risks. Attackers or malicious insiders with access to the _internal index can extract this key and potentially impersonate legitimate users or escalate privileges within the Splunk environment. This could result in unauthorized access to sensitive logs, manipulation or deletion of critical security data, and disruption of monitoring capabilities. Given Splunk's role in security monitoring and incident response, such compromise can blind organizations to ongoing attacks or cause false alerts, impacting incident detection and response. Industries such as finance, government, telecommunications, and critical infrastructure, which heavily rely on Splunk for security analytics, are particularly vulnerable. The medium severity rating reflects the need for authenticated access, but the high impact on confidentiality, integrity, and availability means exploitation could have serious consequences including data breaches, compliance violations (e.g., GDPR), and operational disruptions.

To mitigate CVE-2026-20142, European organizations should: 1) Upgrade Splunk Enterprise to versions 10.2.0, 10.0.2, 9.4.7, 9.3.9, or 9.2.11 or later, where the vulnerability is patched. 2) Restrict access to the _internal index strictly to trusted roles and users, minimizing the number of accounts with such privileges. 3) Audit and monitor access logs for unusual queries or access patterns to the _internal index that might indicate attempts to extract sensitive information. 4) Review and sanitize log configurations to ensure sensitive keys or credentials are not logged in plaintext. 5) Implement role-based access controls (RBAC) and enforce the principle of least privilege within Splunk deployments. 6) Conduct regular security assessments and penetration tests focusing on internal threat vectors and log data exposure. 7) Educate administrators and users about the sensitivity of internal logs and the risks of exposing authentication keys. 8) Consider additional encryption or obfuscation mechanisms for sensitive configuration data within Splunk where feasible.