CVE-2026-33264: airflow Insecure Deserialization — Fix

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0165

Probability of exploitation

0.74%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Affected Products

Vendor	Product	Versions
apache	airflow	< 3.3.0

References

Advisories & Patches

https://github.com/apache/airflow/pull/66002 https://github.com/apache/airflow/pull/68528 https://lists.apache.org/thread/otvdw8qt2y7xy2n5nq9xby9ky4rf5ltj

Other References

http://www.openwall.com/lists/oss-security/2026/07/07/1

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-33264? +

CVE-2026-33264 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0165, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-33264? +

CVE-2026-33264 affects products from apache, specifically: airflow. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-33264? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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