CVE-2026-63138 Overview
CVE-2026-63138 is a NoSQL injection vulnerability in Elastic Kibana that allows authenticated users to retrieve data outside their authorization scope. The flaw stems from improper neutralization of special elements in data query logic [CWE-943]. An attacker with valid credentials can submit crafted input to affected query functionality, altering the intended query semantics and returning unauthorized data. Elastic addressed the issue in Kibana 9.4.5 and 9.5.1 through security update ESA-2026-168.
Critical Impact
Authenticated attackers can read data they are not authorized to access by manipulating NoSQL query logic in Kibana.
Affected Products
- Elastic Kibana versions prior to 9.4.5
- Elastic Kibana 9.5.0
- Elastic Kibana deployments exposing the affected query functionality to authenticated users
Discovery Timeline
- 2026-09-01 - CVE-2026-63138 published to the National Vulnerability Database
- 2026-09-02 - Last updated in NVD database
Technical Details for CVE-2026-63138
Vulnerability Analysis
The vulnerability resides in Kibana query handling logic that constructs NoSQL queries from user-supplied input. Kibana fails to properly neutralize special elements before incorporating input into query structures. This allows an authenticated user to inject operators or clauses that change the query's evaluation. The result is information disclosure, matching CAPEC-676 (NoSQL Injection). The flaw impacts confidentiality but does not affect integrity or availability, since query results are returned rather than data being modified.
Root Cause
The root cause is improper neutralization of special elements used in a data query [CWE-943]. Kibana treats query fragments from authenticated user input as trusted structural components rather than as literal values. When special operators or reserved characters appear in input, the query engine interprets them as syntax, expanding the scope of records matched by the query.
Attack Vector
Exploitation requires network access to Kibana and valid authenticated credentials with access to the affected query functionality. No user interaction is required. The attacker submits specially crafted input to a vulnerable endpoint. The manipulated query executes against the backing datastore and returns records the requesting user is not authorized to view.
No public proof-of-concept exploit code is available at this time. Refer to the Elastic Security Update ESA-2026-168 for vendor-provided technical details.
Detection Methods for CVE-2026-63138
Indicators of Compromise
- Kibana request logs containing NoSQL operator syntax such as $ne, $gt, $where, or $regex embedded in parameter values submitted by non-administrative users.
- Query response volumes or record counts materially larger than a user's typical access pattern.
- Repeated failed or malformed query submissions from a single authenticated session preceding a successful anomalous response.
Detection Strategies
- Enable Kibana audit logging and inspect query parameters for injected operators or unexpected structural characters.
- Correlate authenticated user identity with the volume and sensitivity of records returned from Kibana query endpoints.
- Alert on Kibana versions in the environment that match the vulnerable range through authenticated vulnerability scanning.
Monitoring Recommendations
- Forward Kibana access and audit logs to a centralized SIEM for long-term retention and query anomaly analysis.
- Baseline normal query patterns per user role and alert on deviations in returned record counts or accessed indices.
- Monitor Elasticsearch slow logs for unusual query structures originating from Kibana service accounts.
How to Mitigate CVE-2026-63138
Immediate Actions Required
- Upgrade Kibana to version 9.4.5 or 9.5.1 as directed in Elastic Security Advisory ESA-2026-168.
- Inventory all Kibana deployments and identify instances running affected versions, particularly 9.5.0.
- Review authenticated user access to Kibana and revoke unnecessary query permissions until patching is complete.
Patch Information
Elastic released fixed versions in Kibana 9.4.5 and 9.5.1. Detailed patch and upgrade guidance is documented in the Elastic Security Update ESA-2026-168.
Workarounds
- Restrict access to the affected query functionality using Kibana role-based access controls until the upgrade is applied.
- Place Kibana behind an authenticating reverse proxy that inspects and rejects requests containing NoSQL operator syntax in unexpected parameters.
- Reduce the blast radius by ensuring Kibana service accounts against Elasticsearch use least-privilege document and field-level security.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
