External risk intelligence

Apache Kylin Missing Authorization Vulnerability in Metadata Dump API

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-63619

Apache Kylin is an analytical data warehouse typically deployed within internal network environments to support backend business intelligence and data processing. While the vulnerable API is network-accessible, the software is not designed to be a public-facing service, and common deployment patterns involve placing it behind internal controls and firewalls, making public internet exposure uncommon.

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability in Apache Kylin involves a missing authorization check in an API used for metadata, potentially allowing unauthorized access to sensitive information if Kylin services are exposed to the public internet. However, typical deployments of Kylin are internal, meaning most organizations are likely not at risk.

Unauthorized access to Kylin's metadata.
Only impacts Kylin exposed externally.
Confirm Kylin's network exposure.

Attack Path

How an attacker could exploit the issue

An attacker could potentially access a backend metadata API in Apache Kylin that lacks proper authorization checks. If this API is exposed to the public network, an unauthenticated attacker could use it to view and modify sensitive metadata. This could lead to significant compromise of the Kylin services, though the risk is reduced in typical internal deployments.

Requires public network exposure.
Triggered by accessing metadata dump API.
Risk of sensitive metadata compromise.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could impact Kylin services directly exposed to the public network. Backend metadata could be affected when this API is accessed without proper authorization and path confinement, though such exposure is uncommon, and in-house deployments are typically not impacted.

Backend metadata could be exposed.
API accessed without proper authorization.
Unaffected by common deployments.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Apache Kylin, primarily impacting services directly exposed to the public network, suggests that platform or infrastructure teams managing Kylin deployments should lead the initial response. The first practical move is to identify any instances of Kylin, confirm their exposure and business criticality, and then engage the accountable owner to plan remediation based on risk.

Identify Kylin instances and their exposure.
Confirm business criticality and ownership.
Plan remediation based on risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Apache Kylin?

Apache Kylin is an open-source distributed analytical data warehouse. It is designed to provide multidimensional analysis (OLAP) on large-scale datasets, helping organizations process complex business intelligence queries quickly. It is typically deployed as a backend infrastructure component to support data-driven applications.

What does the Missing Authorization vulnerability in CVE-2026-63619 mean?

This vulnerability is classified as CWE-862, which refers to a failure to verify whether a user has permission to perform an action. In this case, an API endpoint intended for metadata dumps lacks checks for user credentials and path restrictions. This allows an unauthorized person to potentially view or modify sensitive system information that should be protected.

How is this Apache Kylin vulnerability triggered?

An attacker triggers this issue by directly requesting the vulnerable backend metadata dump API. The bug does not require any specific preconditions like prior authentication or user interaction. Importantly, interacting with other standard Kylin services or interfaces that correctly enforce authorization will not trigger this specific vulnerability.

Why should I care about this CVE if my Kylin instance is internal?

Halo Surface Signal indicates that Apache Kylin is usually deployed in internal environments behind firewalls, making public internet exposure rare. If your instance is truly internal and not accessible from the public network, the risk of external exploitation is minimal, though internal security policies should still be maintained.

Do I need to patch my Apache Kylin deployment?

If you are running any version from 4 through 5.0.4, you should prioritize upgrading to version 5.0.5. Start by identifying where Kylin is running in your network and confirming its exposure. Work with the service owner to schedule an upgrade to the fixed version to ensure the metadata API is properly secured.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.