CVE-2026-25604 Overview
A SAML authentication origin verification bypass vulnerability has been identified in the AWS Auth Manager component of Apache Airflow Providers Amazon. The vulnerability occurs because the origin of SAML authentication is accepted as provided by the client without verification against the actual instance URL. This flaw allows attackers to gain unauthorized access to different Airflow instances by reusing SAML responses from other instances, potentially bypassing access controls configured for the target environment.
Critical Impact
Attackers can reuse valid SAML authentication responses across different Apache Airflow instances, allowing cross-instance access with potentially elevated privileges based on the differing access control configurations between instances.
Affected Products
- Apache Airflow Providers Amazon (versions prior to 9.22.0)
Discovery Timeline
- 2026-03-09 - CVE CVE-2026-25604 published to NVD
- 2026-03-10 - Last updated in NVD database
Technical Details for CVE-2026-25604
Vulnerability Analysis
This vulnerability falls under CWE-346: Origin Validation Error, which occurs when an application fails to properly validate the origin of data or communications. In the context of the AWS Auth Manager for Apache Airflow, the authentication mechanism trusts the origin value supplied in SAML responses without cross-referencing it against the legitimate instance URL that should be processing the authentication request.
SAML (Security Assertion Markup Language) authentication relies on a chain of trust between Identity Providers (IdPs) and Service Providers (SPs). A critical component of this trust model is validating that the SAML assertion is intended for the specific service instance receiving it. When this validation is missing, the security boundary between distinct Airflow deployments is compromised.
Root Cause
The root cause of CVE-2026-25604 lies in the AWS Auth Manager's failure to implement proper SAML audience restriction validation. When processing SAML authentication responses, the component accepts the origin/audience value as provided by the client rather than verifying that the SAML response's intended recipient matches the actual instance URL. This design oversight allows SAML responses issued for one Airflow instance to be replayed against other instances within the same federated authentication infrastructure.
Attack Vector
The attack vector for this vulnerability is network-based and requires low-privilege access. An attacker with valid credentials on one Apache Airflow instance can exploit this vulnerability through the following mechanism:
- The attacker authenticates to a legitimate Airflow instance using SAML-based authentication via the AWS Auth Manager
- The attacker captures the SAML response issued by the Identity Provider
- The attacker replays this captured SAML response to a different Airflow instance that shares the same federated authentication infrastructure
- Due to missing origin validation, the target instance accepts the SAML response as valid
- The attacker gains access to the target instance with permissions determined by that instance's access control configuration
This attack is particularly dangerous in multi-tenant environments or organizations running multiple Airflow instances with varying security configurations. An attacker with limited access on a development instance could potentially gain access to production environments with more permissive configurations.
Detection Methods for CVE-2026-25604
Indicators of Compromise
- SAML authentication events where the audience/recipient URL in the assertion does not match the expected instance URL
- Multiple successful authentications using the same SAML assertion across different Airflow instances
- Authentication logs showing session establishment from unexpected source instances
- Unusual access patterns where users appear to authenticate to instances they normally don't access
Detection Strategies
- Implement SAML assertion logging with audience URL validation checks at the application level
- Monitor authentication events for SAML responses with mismatched audience restrictions
- Deploy anomaly detection for cross-instance authentication patterns
- Review AWS CloudTrail logs for unusual authentication activity related to Airflow instances
Monitoring Recommendations
- Enable detailed authentication logging in Apache Airflow for all AWS Auth Manager authentication events
- Configure alerting for failed SAML audience validation attempts after upgrading to version 9.22.0
- Monitor for authentication attempts from unexpected network segments or IP ranges
- Implement session correlation monitoring across multiple Airflow instances
How to Mitigate CVE-2026-25604
Immediate Actions Required
- Upgrade Apache Airflow Providers Amazon to version 9.22.0 or later immediately
- Audit authentication logs for signs of cross-instance SAML response reuse
- Review access control configurations across all Airflow instances to assess potential exposure
- Consider temporarily disabling SAML authentication via AWS Auth Manager until the upgrade is complete if immediate patching is not possible
Patch Information
Apache has released version 9.22.0 of the Airflow Providers Amazon package which addresses this SAML origin validation bypass. The fix implements proper verification of the SAML response origin against the actual instance URL, ensuring that SAML assertions cannot be replayed across different Airflow deployments.
The security patch can be reviewed in the GitHub Pull Request 61368. Additional technical details are available in the Apache Mailing List Thread and the Openwall OSS Security Post.
Workarounds
- Implement network segmentation to isolate Airflow instances with different security requirements
- Configure Web Application Firewalls (WAF) to inspect and validate SAML response patterns
- Use distinct Identity Provider configurations for each Airflow instance to prevent cross-instance token reuse
- Deploy additional authentication layers such as IP-based access restrictions or VPN requirements for sensitive instances
# Upgrade Apache Airflow Providers Amazon to patched version
pip install apache-airflow-providers-amazon>=9.22.0
# Verify the installed version
pip show apache-airflow-providers-amazon | grep Version
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
