CVE-2026-33264: Apache Airflow

Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days.

A bug in `BaseSerialization.deserialize()` allowed unrestricted `import_string()` of attacker-controlled class paths when the Scheduler / API Server loaded a serialized DAG: a DAG author could embed a malicious trigger into a DAG to gain remote code execution on the API Server / Scheduler process, crossing the Airflow security boundary that DAG-author code must never execute in those processes. Users are advised to upgrade to `apache-airflow` 3.3.0 or later. As a defense-in-depth mitigation, deployments where DAG-author trust is limited can restrict the `[core] allowed_deserialization_classes` config to a narrow allowlist.

Affected products

• Apache Airflow: before 3.3.0 (fixed in 3.3.0)

Published 2026-07-07. Last modified 2026-07-08.