Executive Summary

CVE-2026-4498 is a vulnerability in Kibana's Fleet plugin debug route handlers where these handlers execute with unnecessary privileges. This flaw allows an authenticated Kibana user who has Fleet sub-feature privileges (such as managing agents, agent policies, or settings) to read Elasticsearch index data beyond what their direct RBAC permissions allow.

The issue is classified as Execution with Unnecessary Privileges (CWE-250) and involves privilege abuse (CAPEC-122). It affects Kibana versions 8.0.0 through 8.19.13 and 9.0.0 through 9.2.7 and 9.3.0 through 9.3.2, with Fleet enabled by default.

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Impact Analysis

This vulnerability can lead to unauthorized access to sensitive Elasticsearch index data by users who should not have such access, due to privilege escalation within Kibana's Fleet plugin.

The impact is primarily on confidentiality, as attackers can read data beyond their authorized scope. There is no impact on data integrity or system availability.

Because the vulnerability requires an authenticated user with Fleet privileges, the risk is higher if those privileges are widely granted or not properly restricted.

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Detection Guidance

This vulnerability can be detected by enabling Kibana audit logging and monitoring HTTP requests to specific Fleet debug routes.

Specifically, enable audit logging by setting the configuration option xpack.security.audit.enabled to true.

Once audit logging is enabled, monitor for HTTP requests to the following paths which indicate potential exploitation attempts:

• /internal/fleet/debug/index
• /internal/fleet/debug/saved_objects

Suggested commands include using tools like curl or network monitoring utilities to check for requests to these paths, or querying Kibana audit logs for entries containing these endpoints.

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Mitigation Strategies

The primary mitigation is to upgrade Kibana to a fixed version:

• Upgrade to Kibana 8.19.14, 9.2.8, or 9.3.3 or later.

If immediate upgrade is not possible, restrict Fleet privileges by reviewing and limiting custom roles that grant Fleet sub-feature privileges.

• Limit roles such as agents_all, agent_policies_all, and settings_all to trusted administrative users only.

Additionally, enable Kibana audit logging (xpack.security.audit.enabled: true) to detect and monitor any exploitation attempts.

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Compliance Impact

This vulnerability allows an authenticated Kibana user with Fleet sub-feature privileges to read Elasticsearch index data beyond their authorized RBAC scope, resulting in a high confidentiality impact.

Such unauthorized access to sensitive data can lead to violations of data protection regulations and standards like GDPR and HIPAA, which require strict controls on data access and confidentiality.

Therefore, exploitation of this vulnerability could compromise compliance by exposing protected or regulated data to users without proper authorization.

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