CVE-2026-59243 Apache Software Foundation CVE debrief

Who should care

Apache Airflow Providers Fab users, especially those with Azure AD OAuth login configured, should upgrade to version 3.7.3 or later to prevent authentication bypass attacks. This is a critical vulnerability requiring immediate attention. Users should verify and enforce secure configuration of Azure AD OAuth login and monitor for suspicious authentication attempts. Additionally, users should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Users should also plan vendor-supported updates or mitigations through normal change control where exposure is confirmed. Compensating controls for exposed systems should be reviewed while remediation is scheduled and verified. Relevant monitoring, detection, and logs for exposed assets should be checked for extra review. Exceptions, retest remediated assets, and close the item only after evidence is documented. Asset inventory and source tracking are also recommended to ensure thorough vulnerability management. Security teams should prioritize this vulnerability and coordinate with operators and platform teams to ensure timely remediation. Vulnerability management processes should be reviewed to prevent similar issues in the future. This requires coordination with security teams and operators to ensure that affected systems are identified and remediated promptly. The vulnerability management team should track the remediation progress and verify that all affected systems have been updated to version 3.7.3 or later. The security team should also review compensating controls for exposed systems and ensure that monitoring and detection are in place to identify potential attacks. The security team should also review the CVE record and vendor advisory to validate the affected scope and severity. The security team should also plan for vendor-supported updates or mitigations through normal change control where exposure is confirmed. The security team should also review relevant monitoring, detection, and logs for exposed assets that need extra review. The security team should also track exceptions, retest remediated assets, and close the item only after evidence is is is

Technical summary

The FAB auth manager's Azure AD OAuth login defaulted `verify_signature=False` when decoding the ID token, allowing an attacker to bypass authentication with a forged or unsigned ID token. This issue affects `apache-airflow-providers-fab` before 3.7.3. The vulnerability has a CVSS score of 9.8 and a severity of CRITICAL. Users are advised to upgrade to `apache-airflow-providers-fab` 3.7.3, which defaults `verify_signature=True`.

Defensive priority

Critical vulnerability in Apache Airflow Providers Fab, requiring immediate attention to upgrade to version 3.7.3 or later.

Recommended defensive actions

• Upgrade to apache-airflow-providers-fab version 3.7.3 or later
• Verify and enforce secure configuration of Azure AD OAuth login
• Monitor for suspicious authentication attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The FAB auth manager's Azure AD OAuth login defaulted to `verify_signature=False` when decoding the ID token, allowing an attacker to bypass authentication with a forged or unsigned ID token. This issue affects `apache-airflow-providers-fab` before 3.7.3. Users are advised to upgrade to `apache-airflow-providers-fab` 3.7.3.

Official resources