CVE-2025-68438
📋 TL;DR
This vulnerability in Apache Airflow exposes sensitive values like passwords and API keys in cleartext in the Rendered Templates UI when template fields exceed maximum length. It affects Airflow users with custom secret masking patterns who haven't upgraded to version 3.1.6. The issue occurs because user-registered mask_secret() patterns weren't included during serialization before truncation.
💻 Affected Systems
- Apache Airflow
📦 What is this software?
Airflow by Apache
⚠️ Risk & Real-World Impact
Worst Case
Attackers with access to the Airflow UI could extract all sensitive credentials, secrets, and API keys stored in Airflow, leading to complete system compromise and data breaches.
Likely Case
Authorized users or attackers with UI access can view exposed secrets in rendered templates, potentially gaining unauthorized access to downstream systems and services.
If Mitigated
With proper network segmentation and access controls, only authorized administrators could see exposed secrets, limiting the blast radius.
🎯 Exploit Status
Exploitation requires access to the Airflow UI and knowledge of which DAGs have template fields exceeding length limits with sensitive data.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.1.6 or later
Vendor Advisory: https://lists.apache.org/thread/55n7b4nlsz3vo5n4h5lrj9bfsk8ctyff
Restart Required: Yes
Instructions:
1. Backup your Airflow configuration and database. 2. Upgrade Apache Airflow to version 3.1.6 or later using pip: 'pip install --upgrade apache-airflow==3.1.6'. 3. Restart all Airflow services including webserver, scheduler, and workers. 4. Verify the upgrade completed successfully.
🔧 Temporary Workarounds
Reduce max_templated_field_length
allLower the maximum template field length to prevent fields from exceeding the limit where truncation occurs.
Set [core] max_templated_field_length to a lower value in airflow.cfg
Disable Rendered Templates UI
allRestrict access to the Rendered Templates UI through network controls or authentication.
Configure webserver authentication or network ACLs to block access to /rendered-templates endpoints
🧯 If You Can't Patch
- Implement strict access controls to limit who can access the Airflow UI
- Audit all DAGs to ensure sensitive values aren't stored in template fields that could exceed length limits
🔍 How to Verify
Check if Vulnerable:
Check Airflow version and verify if custom mask_secret() patterns are used with template fields that could exceed max_templated_field_length.Check Version:
airflow version | grep 'apache-airflow'Verify Fix Applied:
After upgrading to 3.1.6+, test that sensitive values in template fields exceeding length limits are properly masked in the Rendered Templates UI.📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to /rendered-templates endpoints
- Multiple failed authentication attempts to Airflow UI
Network Indicators:
- Unusual traffic to Airflow webserver from unexpected IPs
- Large data extraction from Airflow UI endpoints
SIEM Query:
source="airflow-webserver" AND (uri_path="/rendered-templates" OR uri_path="/template") AND (src_ip NOT IN allowed_admin_ips)