Apache Airflow: Authenticated RCE via XCom PATCH endpoint — XComUpdateBody missing FORBIDDEN_XCOM_KEYS validator
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and GitHub. Impact type from CWE-502.
Summary
A bug in Apache Airflow's XCom PATCH endpoint `PATCH /api/v2/xcomEntries/{key}` allowed an authenticated UI/API user with XCom write permission on a Dag to set XCom entries under reserved key names (e.g. `return_value`) that the matching POST endpoint already validated against `FORBIDDEN_XCOM_KEYS`. The endpoint also accepted serialized payload shapes the triggerer's deserializer treats as code; combined, this allowed RCE on the triggerer when the affected task next deferred. Affects deployments where untrusted users have XCom write permission on Dags that defer to the triggerer. This is a fix-bypass of CVE-2026-33858: PR #64148 added the `FORBIDDEN_XCOM_KEYS` validator only on the POST/set path; the PATCH path was not covered. Users who already upgraded for CVE-2026-33858 should additionally upgrade to `apache-airflow` 3.2.2 or later to cover the PATCH-path bypass.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Apache | Apache Airflow | 3.2.0 to before 3.2.2 | 3.2.2 | Patch available | CNA |
| — | apache-airflow (PyPI) | 3.2.0 to before 3.2.2 | 3.2.2 | Patch available | GHSA-wr76-29cr-67w8 |
- Apache Airflow VendorApache Affected 3.2.0 to before 3.2.2 Fixed in 3.2.2 Patch available CNA
- apache-airflow (PyPI) Vendor— Affected 3.2.0 to before 3.2.2 Fixed in 3.2.2 Patch available GHSA-wr76-29cr-67w8
Remediation
- Fix · CNA Apache Airflow (Apache Software Foundation) Fixed in 3.2.2
- Fix · GHSA-wr76-29cr-67w8 apache-airflow (PyPI) Fixed in 3.2.2 Advisory →
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Apache Airflow 3.2.2
17 records Highest priority Priority MEDIUM 3 MEDIUM, 14 LOW
Other records, highest priority first
- TI-2026-30568 Apache Airflow: BashOperator Jinja2 injection via dag_run.conf — low-privilege user patternPriority MEDIUM 47
- TI-2026-36484 Apache Airflow: JWT Token Exposure in KubernetesExecutor Command-Line ArgumentsPriority MEDIUM 41
- TI-2026-33151 Apache Airflow: Arbitrary import in custom deadline-reference deserializationPriority LOW 39
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42359
- 2026-10-03 Alias added: GHSA-wr76-29cr-67w8
- 2026-10-25 EPSS moved to the below the 50th percentile
- 2026-11-03 Fix available: [email protected] · CNA
References
Advisory 3
More Apache Airflow vulnerabilities
- TI-2020-10905 Missing authentication in Apache Airflow KEVCVSS 3.1CRITICAL 9.8
- TI-2020-09638 OS command injection in Apache Airflow KEVCVSS 3.1HIGH 8.8
- TI-2022-19017 Apache Airflow <2.4.0 has an RCE in a bash example CVSS 3.1HIGH 8.8
- TI-2021-16140 Apache Airflow: Variable Import endpoint missed authentication check CVSS 3.1CRITICAL 9.8
- TI-2022-08169 Apache Airflow: RCE in example DAGs CVSS 3.1HIGH 8.8
- TI-2024-26776 Apache Airflow: DAG Author Code Execution possibility in airflow-scheduler CVSS 3.1HIGH 8.8
Sources
- CVE-2026-42359 · CVE Program
- CVE-2026-42359 · NVD
- FIRST EPSS
- GHSA-wr76-29cr-67w8 · GitHub Advisory Database · CC BY 4.0
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