{"id":"CVE-2026-40861","aliases":["BIT-airflow-2026-40861","GHSA-89cj-xrpx-j79m","PYSEC-2026-181"],"url":"https://o3.security/vulnerability/CVE-2026-40861","summary":"Apache Airflow: Arbitrary File Read via Log Symlink following in FileTaskHandler","details":"A Dag author could either (a) create a symlink under their task's log directory pointing to an arbitrary file readable by the API server process (read-path attack — e.g. `/etc/passwd` or `airflow.cfg`) or (b) supply a `task_id` containing `..` sequences accepted by the Task SDK's `KEY_REGEX` (write-path attack), and in both cases the FileTaskHandler resolves the log path outside the configured `base_log_folder`, leaking or overwriting arbitrary files. Only affects deployments where the worker log folder is shared with the API server. Users are advised to upgrade to `apache-airflow` 3.2.2 or later. As a defense-in-depth mitigation, deploy the worker and API server with separate log volumes so that worker-controlled paths cannot reach the API server's filesystem.","published":"2026-06-01T07:55:37.566Z","modified":"2026-08-12T03:51:08.951914272Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.00691,"percentile":0.50075,"asOf":"2026-08-24"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"apache-airflow","fixedVersion":"3.2.2"}],"fix":{"url":"https://github.com/apache/airflow/pull/65325","label":"apache/airflow#65325"},"references":[{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2026/05/31/1"},{"type":"WEB","url":"https://pypi.python.org"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40861.json"},{"type":"ADVISORY","url":"https://lists.apache.org/thread/823334db2559xjlwt59gpzjz47thnscl"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40861"},{"type":"FIX","url":"https://github.com/apache/airflow/pull/65325"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:08.951914272Z"}}