CVE-2026-62393 Overview
CVE-2026-62393 is an authorization flaw in Apache Kylin, an open-source distributed analytics engine for big data. The vulnerability stems from improper handling of insufficient permissions during job information retrieval. An authenticated attacker can access job metadata belonging to projects they are not authorized to view. The issue is classified as [CWE-280: Improper Handling of Insufficient Permissions or Privileges].
Apache Kylin versions 4 through 5.0.3 are affected. The Apache Kylin project has released version 5.0.4 to remediate the issue.
Critical Impact
An authenticated attacker with low privileges can retrieve job information from unauthorized projects across the Kylin deployment, exposing sensitive metadata about analytics workloads and organizational data pipelines.
Affected Products
- Apache Kylin 4.x (all versions)
- Apache Kylin 5.0.0 through 5.0.3
- Fixed in Apache Kylin 5.0.4
Discovery Timeline
- 2026-07-14 - CVE-2026-62393 published to NVD
- 2026-07-14 - Apache Security disclosure posted to the Apache Security Mailing List and Openwall OSS Security
- 2026-07-15 - Last updated in NVD database
Technical Details for CVE-2026-62393
Vulnerability Analysis
Apache Kylin exposes REST APIs to manage and monitor analytical jobs. These jobs are scoped to projects, and access to job metadata should be restricted based on project membership and role assignments. The vulnerability breaks that isolation model.
When a user queries job information, the affected code paths do not consistently verify whether the requesting principal has permission to view jobs in the target project. Because authentication is required but project-level authorization is not enforced, any authenticated user can enumerate or retrieve job details across project boundaries.
The disclosed impact is limited to confidentiality of job information. Integrity and availability of the analytics platform are not directly affected by this specific weakness.
Root Cause
The root cause is a missing or incomplete authorization check in the job information retrieval logic. Apache Kylin's multi-tenant project model relies on server-side enforcement of project scope. In affected versions, that enforcement is absent for at least one job-related endpoint, resulting in [CWE-280] behavior where the code fails to handle a lack of permissions correctly and returns data instead of denying the request.
Attack Vector
Exploitation requires an attacker to hold valid credentials for the Kylin instance. Once authenticated, the attacker sends crafted requests to the job information API referencing project or job identifiers outside their assigned scope. The server returns job metadata that should have been restricted.
No verified public proof-of-concept has been published. There is no working code example released alongside the advisory, and the Apache Security advisory describes the flaw at a design level without exploit details.
// No public proof-of-concept is available.
// See the Apache Security advisory for authoritative details:
// https://lists.apache.org/thread/xg8dcyjw0nkq5y8dhq3r25x3rxc62x9j
Detection Methods for CVE-2026-62393
Indicators of Compromise
- Access log entries showing a single authenticated user querying job endpoints across many distinct project identifiers in a short window.
- HTTP 200 responses from Kylin job APIs returning data for projects the requesting user is not a member of.
- Enumeration patterns against job ID ranges or project ID parameters in the Kylin REST API.
Detection Strategies
- Review Apache Kylin application logs for job information API calls and correlate the requesting user against the target project membership.
- Deploy web application firewall or reverse proxy rules that log the project parameter on job endpoints and flag cross-project access anomalies.
- Compare the running Kylin version against the fixed release 5.0.4 using deployment inventory or configuration management data.
Monitoring Recommendations
- Forward Kylin access and audit logs to a centralized logging or SIEM platform and build queries that group job API access by user and project.
- Alert on authenticated users generating unusually high volumes of job metadata requests, especially spanning multiple projects.
- Track upgrade status of Apache Kylin instances as an ongoing configuration metric until all nodes report version 5.0.4 or later.
How to Mitigate CVE-2026-62393
Immediate Actions Required
- Upgrade all Apache Kylin deployments from versions in the 4.x through 5.0.3 range to version 5.0.4.
- Audit existing Kylin user accounts and revoke credentials that are no longer needed to reduce the pool of principals that can trigger the flaw.
- Review recent job API access logs for signs of cross-project enumeration prior to patching.
Patch Information
Apache Kylin 5.0.4 contains the fix for CVE-2026-62393. Administrators should follow the upstream upgrade procedure and validate that job endpoints correctly enforce project-level authorization after the upgrade. Refer to the Apache Security Mailing List Thread for the authoritative advisory.
Workarounds
- Restrict network access to the Kylin REST API so that only trusted internal clients and service accounts can reach job endpoints.
- Tighten account provisioning so only necessary users hold Kylin credentials, since the flaw requires authentication.
- Place Kylin behind a reverse proxy that enforces additional authorization checks on job API paths until the upgrade is complete.
# Example: verify the running Apache Kylin version before and after upgrade
$KYLIN_HOME/bin/kylin.sh version
# Expected output after remediation
# Apache Kylin 5.0.4
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
