Apache Airflow exception-node deserialization permits arbitrary callable execution
High8.8CVE-2026-58076 · Published Aug 12, 2026 · updated Oct 2, 2026
Apache Airflow's serialization layer reconstructed exception nodes by calling `import_string()` on a class name taken from the serialized blob and instantiating it with arguments from the same blob, with no restriction on what could be imported. An operator's `executor_config` reaches that branch, so a Dag author could place a value there that causes an arbitrary callable to be imported and invoked -- for example `subprocess.check_output`, or `builtins.eval` on the `builtins`-prefixed variant. The code runs in the **Scheduler**, which reconstructs serialized Dags in its normal loop with no request involved, and in the **API server**, on any authenticated read of the Dag such as `GET /api/v2/dags/{dag_id}/details`. Both are components the Airflow security model states must never execute Dag-author code, and both hold the metadata database credentials and the JWT signing secret. No non-default configuration is required. This is a **different sink from CVE-2026-33264**, which covered only the trigger branch of the same deserializer: deployments that upgraded in response to that advisory are still affected through the exception branch and must upgrade again. Users are advised to upgrad...
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| apache-airflow PyPI | >= 3.3.0, < 3.3.1 | 3.3.1 |
Details and references
Apache Airflow's serialization layer reconstructed exception nodes by calling `import_string()` on a class name taken from the serialized blob and instantiating it with arguments from the same blob, with no restriction on what could be imported. An operator's `executor_config` reaches that branch, so a Dag author could place a value there that causes an arbitrary callable to be imported and invoked -- for example `subprocess.check_output`, or `builtins.eval` on the `builtins`-prefixed variant. The code runs in the **Scheduler**, which reconstructs serialized Dags in its normal loop with no request involved, and in the **API server**, on any authenticated read of the Dag such as `GET /api/v2/dags/{dag_id}/details`. Both are components the Airflow security model states must never execute Dag-author code, and both hold the metadata database credentials and the JWT signing secret. No non-default configuration is required. This is a **different sink from CVE-2026-33264**, which covered only the trigger branch of the same deserializer: deployments that upgraded in response to that advisory are still affected through the exception branch and must upgrade again. Users are advised to upgrade to apache-airflow 3.3.1 or later, which restricts the imported class to a subclass of `BaseException`.
- CVSS 3.1
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-502
- Also known as
- BIT-airflow-2026-58076, CVE-2026-58076, PYSEC-2026-3991
- nvd.nist.gov/vuln/detail/CVE-2026-58076
- github.com/apache/airflow/pull/68511
- github.com/apache/airflow/commit/3a08a3d7792335ac9456cd44c92d8de3ae0d6ec1
- github.com/apache/airflow/commit/560f117525d201ed64327c4185050705339e07b1
- github.com/apache/airflow
- github.com/apache/airflow/releases/tag/3.3.1
- github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2026-3991.yaml
- lists.apache.org/thread/t81p688t15jozxsng8521o60nh2kfsos
- www.cve.org/CVERecord?id=CVE-2026-33264
More Apache Airflow advisories
All Apache Airflow| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Aug 12 | Apache Airflow missing team context permits cross-team Dag actions and XCom reads Medium6.5Aug 12 | Medium6.5 | 3.3.1 |
| Aug 12 | Apache Airflow bulk endpoints log Variable and Connection secrets in cleartextMedium6.5Aug 12 | Medium6.5 | 3.3.1 |
| Aug 12 | Apache Airflow Task SDK fails to mask list-shaped JSON VariablesMedium6.5Aug 12 | Medium6.5 | 3.3.1 |
| Aug 12 | Apache Airflow Task SDK Callback deserialization can import arbitrary modules in the schedulerHigh8.8Aug 12 | High8.8 | 3.3.1 |
| Aug 12 | Apache Airflow environment-variable secrets backend permits cross-team credential useMedium5.4Aug 12 | Medium5.4 | 3.3.1 |
| Aug 12 | Apache Airflow Config API exposes team-scoped sensitive configuration valuesMedium6.5Aug 12 | Medium6.5 | 3.3.1 |