CVE-2026-26938 is a vulnerability classified under CWE-1336, which pertains to improper neutralization of special elements used in a template engine. Specifically, this vulnerability exists in the Workflows feature of Elastic Kibana version 9.3.0. The flaw allows an attacker who is authenticated and possesses the workflowsManagement:executeWorkflow privilege to inject malicious code into the template engine. This code injection can be leveraged to read arbitrary files from the Kibana server's filesystem, potentially exposing sensitive configuration files, credentials, or logs. Additionally, the injected code can perform Server-Side Request Forgery (SSRF), enabling the attacker to make unauthorized requests from the Kibana server to internal or external systems, potentially bypassing network restrictions. The vulnerability does not require user interaction beyond authentication, and the attack surface is limited to users with specific workflow execution privileges. The CVSS v3.1 base score is 8.6, indicating high severity, with network attack vector, low attack complexity, no privileges required (PR:N in vector likely means no additional privileges beyond authentication), no user interaction, and a scope change. The vulnerability impacts confidentiality severely but does not affect integrity or availability. No patches or exploits are currently publicly available, but the risk is significant given the potential for sensitive data disclosure and internal network reconnaissance or exploitation via SSRF.

The primary impact of CVE-2026-26938 is the compromise of confidentiality through unauthorized access to arbitrary files on the Kibana server. This can lead to exposure of sensitive data such as credentials, configuration files, or logs, which may further facilitate lateral movement or privilege escalation within an organization. The SSRF capability allows attackers to pivot from the Kibana server to internal network resources, potentially accessing internal services that are not exposed externally, leading to further compromise. Organizations relying on Kibana for monitoring, logging, or analytics may face significant data breaches or operational risks if this vulnerability is exploited. Since the vulnerability requires authenticated access with specific privileges, insider threats or compromised user accounts pose a heightened risk. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits rapidly after disclosure. The vulnerability could be leveraged in targeted attacks against organizations with critical infrastructure or sensitive data monitored via Elastic Stack.

To mitigate CVE-2026-26938, organizations should first apply any official patches or updates released by Elastic for Kibana version 9.3.0 or later versions that address this vulnerability. In the absence of patches, restrict the workflowsManagement:executeWorkflow privilege to only trusted and necessary users, minimizing the attack surface. Implement strict access controls and monitor user activities related to workflow execution. Employ network segmentation to limit the ability of Kibana servers to reach sensitive internal resources, thereby reducing SSRF impact. Enable robust authentication mechanisms such as multi-factor authentication to reduce the risk of compromised accounts. Regularly audit Kibana logs for unusual file access or workflow execution patterns indicative of exploitation attempts. Consider deploying Web Application Firewalls (WAFs) with rules to detect and block suspicious template injection or SSRF attempts. Finally, maintain an incident response plan to quickly address any signs of compromise related to this vulnerability.