Description
Apache Airflow's XCom `GET /api/v2/{...}/xcomEntries/{key}?deserialize=true` endpoint passed a string-literal payload through `BaseXCom.deserialize_value` without the `_check_forbidden_xcom_keys` guard, allowing an authenticated API user with XCom write-and-read access to instantiate arbitrary `airflow.*` classes on the API server (CWE-502). An authenticated user who can write an XCom value and then read it back with `deserialize=true` triggers the unsafe instantiation. Users are advised to upgrade to apache-airflow 3.3.1 or later, which rejects reserved XCom serialization keys submitted as JSON string literals.
Affected products
apache: airflow
References3
- lists.apache.org/thread/dm0520yhh4mn7qknyoh45r2w6c5qg2mg Mailing ListVendor Advisory
- github.com/apache/airflow/pull/69378 Issue TrackingPatch
- www.openwall.com/lists/oss-security/2026/08/12/6 Mailing ListThird Party Advisory
Metrics
- CVSS 3.1
-
5.4
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - EPSS — exploit probability
- 1% percentile: 45 · as of 12 November 2026
- CWE
- CWE-502
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