Deserialization in Apache Airflow
CVE-2026-33264
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.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.016 (75.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 75.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000
Affected products
- Apache Airflow
- Apache Software Foundation Airflow — versions 0
Weakness classification (CWE)
References
- github.com/apache/airflow/pull/66002 (Patch, patch, Issue Tracking)
- github.com/apache/airflow/pull/68528 (Patch, patch, Issue Tracking)
- lists.apache.org/thread/otvdw8qt2y7xy2n5nq9xby9ky4rf5ltj (vendor-advisory, Mailing List, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-33264?
- CVE-2026-33264 is a critical-severity vulnerability in Apache Airflow, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-07-07.
- How severe is CVE-2026-33264?
- Critical severity. CVSS v3 base score is 9.8 out of 10.