---
id: CVE-2026-33264
aliases:
  - PYSEC-2026-2082
  - BIT-airflow-2026-33264
  - GHSA-2943-9672-r45w
title: >-
  A bug in `BaseSerialization.deserialize()` allowed unrestricted
  `import_string()` of attacker-controlled class paths when the Scheduler /…
summary: >-
  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…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: apache-airflow
product: apache-airflow
ecosystem: pip
affected:
  - apache-airflow < 3.3.0
patched:
  - apache-airflow 3.3.0
published: '2026-07-07'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T11:15:09.025887119Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/PYSEC-2026-2082'
references:
  - url: 'http://www.openwall.com/lists/oss-security/2026/07/07/1'
  - url: 'https://lists.apache.org/thread/otvdw8qt2y7xy2n5nq9xby9ky4rf5ltj'
  - url: 'https://github.com/apache/airflow/pull/66002'
  - url: 'https://github.com/apache/airflow/pull/68528'
  - url: 'https://github.com/advisories/GHSA-2943-9672-r45w'
tags:
  - osv
  - pip
epss: 0.01649
epssPercentile: 0.75457
ingestedAt: '2026-07-09T18:56:35.391Z'
---

## Overview

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 packages

- `apache-airflow < 3.3.0`

## Remediation

Upgrade to a patched release:

- `apache-airflow 3.3.0`