CVE-2026-33264
Apache Airflow: DAG author RCE on webserver via unrestricted import_string() in BaseSerialization.deserialize()
Description
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.
How to fix CVE-2026-33264
To remediate CVE-2026-33264, upgrade the affected package to a fixed version below.
- —upgrade to 3.3.0 or later
- —upgrade to 3.3.0 or later
Is CVE-2026-33264 being exploited?
Low — EPSS is 1.6%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 3.3.0
- from 0, < 3.3.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |