CVE-2026-42359
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…
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | apache-airflow | >= 3.2.0, < 3.2.2 | 3.2.2 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Apache | Airflow | from 3.2.0 before 3.2.2 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-wr76-29cr-67w8
- https://nvd.nist.gov/vuln/detail/CVE-2026-42359
- https://github.com/apache/airflow/pull/65915
- https://lists.apache.org/thread/g8dqykpf1p90tysq8tln4qtkqwb1038s
- https://www.cve.org/CVERecord?id=CVE-2026-33858
- https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2026-185.yaml