CVE-2026-40690: Apache Airflow Information Disclosure Flaw

CVE-2026-40690 Overview

CVE-2026-40690 is a Broken Access Control vulnerability in Apache Airflow that allows unauthorized information disclosure through the asset dependency graph feature. The vulnerability exists because the asset dependency graph does not properly enforce DAG read permissions when users browse assets. A user with read access to at least one DAG can exploit this flaw to browse the asset graph for any other asset in the deployment, effectively learning the existence and names of DAGs and assets that should be outside their authorized scope.

Critical Impact

Authenticated users can enumerate sensitive DAG and asset names across the entire Airflow deployment, potentially exposing confidential workflow information and infrastructure details to unauthorized parties.

Affected Products

• Apache Airflow versions prior to 3.2.1

Discovery Timeline

• 2026-04-24 - CVE-2026-40690 published to NVD
• 2026-04-27 - Last updated in NVD database

Technical Details for CVE-2026-40690

Vulnerability Analysis

This vulnerability is classified under CWE-1220 (Insufficient Granularity of Access Control). The core issue lies in Apache Airflow's asset dependency graph visualization feature, which fails to apply the same permission checks that govern DAG read access. When a user authenticates and gains read permission on any single DAG, the asset dependency graph rendering logic does not filter nodes based on the user's actual authorization scope. This architectural oversight means the graph displays all assets and their relationships across the entire deployment, regardless of whether the user should have visibility into those specific DAGs.

The information exposure enables attackers to map out an organization's workflow infrastructure, understand data dependencies, and identify potentially valuable targets for further exploitation. While this vulnerability does not allow modification of assets or execution of unauthorized DAGs, the disclosed information could be leveraged in reconnaissance activities for more targeted attacks.

Root Cause

The root cause is insufficient granularity of access control in the asset dependency graph rendering component. The application correctly enforces read permissions at the individual DAG level but fails to apply equivalent permission filtering when constructing and displaying the aggregate asset dependency graph view. This creates a bypass where authenticated users can access metadata about resources they should not be able to see.

Attack Vector

The attack vector is network-based and requires low-privileged authenticated access. An attacker must first obtain valid credentials with read access to at least one DAG in the Airflow deployment. Once authenticated, the attacker can navigate to the asset dependency graph interface and browse all available nodes, regardless of their actual permission boundaries.

The vulnerability does not require user interaction and can be exploited through the standard Airflow web interface. The attack has low complexity since it exploits the normal functionality of the asset graph feature rather than requiring specialized techniques or payloads.

Detection Methods for CVE-2026-40690

Indicators of Compromise

• Unusual access patterns to the asset dependency graph endpoint by users with limited DAG permissions
• High-volume or automated requests to asset graph API endpoints from single user sessions
• Users accessing asset metadata for DAGs outside their assigned permission scope
• Anomalous browsing behavior in the Airflow web UI focusing on asset exploration

Detection Strategies

• Implement audit logging for all asset dependency graph access requests and correlate with user permission levels
• Monitor for users repeatedly accessing asset graph features while having minimal DAG read permissions
• Deploy application-layer detection rules to identify enumeration patterns in asset graph queries
• Review web server logs for systematic traversal of asset endpoints by single user accounts

Monitoring Recommendations

• Enable comprehensive access logging in Apache Airflow to capture all user interactions with the asset graph
• Configure alerting for users accessing asset information beyond their designated permission boundaries
• Establish baseline access patterns for the asset dependency graph feature and alert on deviations
• Integrate Airflow logs with SIEM solutions for centralized monitoring and correlation with other security events

How to Mitigate CVE-2026-40690

Immediate Actions Required

• Upgrade Apache Airflow to version 3.2.1 or later immediately to remediate this vulnerability
• Review access logs to identify any potential exploitation of this vulnerability prior to patching
• Audit current user permissions and apply the principle of least privilege to DAG read access
• Consider restricting access to the asset dependency graph feature until the patch is applied

Patch Information

Apache has released version 3.2.1 which addresses this vulnerability by implementing proper permission filtering in the asset dependency graph. The fix ensures that users can only view asset nodes and relationships for DAGs they have explicit read access to. Organizations should upgrade to this version as soon as possible.

For additional details, refer to the GitHub Pull Request containing the fix and the Apache Mailing List Thread with the official security announcement.

Workarounds

• Disable or restrict access to the asset dependency graph feature at the web server or load balancer level until patching is complete
• Implement network segmentation to limit which users can access the Airflow web interface
• Deploy additional authentication controls to restrict access to users with legitimate business needs
• Use web application firewall rules to block requests to asset graph endpoints from users without full DAG access

# Example: Restrict access to asset graph endpoint via nginx
# Add to your nginx configuration for Airflow
location /object/asset_details {
    # Restrict to specific IP ranges or authenticated admins only
    allow 10.0.0.0/8;
    deny all;
}