{"id":"CVE-2026-59242","aliases":["BIT-airflow-2026-59242","GHSA-fcmm-42r9-mmmm","PYSEC-2026-3992"],"url":"https://o3.security/vulnerability/CVE-2026-59242","summary":"Apache Airflow: Arbitrary airflow.* class instantiation on the API server via the XCom deserialize endpoint","details":"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.","published":"2026-08-12T15:35:00.763Z","modified":"2026-10-21T02:58:49.117950175Z","cvss":{"score":5.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"apache-airflow","fixedVersion":"3.3.1"}],"fix":{"url":"https://github.com/apache/airflow/pull/69378","label":"apache/airflow#69378"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/08/12/6"},{"type":"WEB","url":"https://pypi.python.org"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59242.json"},{"type":"ADVISORY","url":"https://lists.apache.org/thread/dm0520yhh4mn7qknyoh45r2w6c5qg2mg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59242"},{"type":"FIX","url":"https://github.com/apache/airflow/pull/69378"},{"type":"WEB","url":"https://github.com/apache/airflow/commit/78abd3044654d44d711eb61e475029fd1b1ccc23"},{"type":"WEB","url":"https://github.com/apache/airflow/commit/d08ddc0127d5be7f9b31c1f935bc4d25a897a848"},{"type":"PACKAGE","url":"https://github.com/apache/airflow"},{"type":"WEB","url":"https://github.com/apache/airflow/releases/tag/3.3.1"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2026-3992.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:58:49.117950175Z"}}