CVE-2026-40861

In Apache Airflow versions before 3.1.6, when rendered template fields in a Dag exceed [core] max_templated_field_length, sensitive values could be exposed in cleartext in the Rendered Templates UI. This occurred because serialization of those fields used a secrets masker instance that did not include user-registered mask_secret() patterns, so secrets were not reliably masked before truncation and display. Users are recommended to upgrade to 3.1.6 or later, which fixes this issue.

A bug in `BaseSerialization.deserialize()` allowed unrestricted `import_string()` of attacker-controlled class paths when the Scheduler / API Server loaded a serialized DAG. A DAG author could embed a malicious trigger into a DAG to gain remote code execution on the API Server / Scheduler process, crossing the Airflow security boundary.

Apache Airflow documentation contained a `BashOperator` code example without proper quoting, allowing shell metacharacter injection via the `conf` field in the DAG trigger API. An authenticated user with `Dag.can_trigger` permission could execute arbitrary commands on the worker.

In Apache Airflow, the asset materialization endpoint (`POST /api/v2/assets/{asset_id}/materialize`) and the XCom result check on `wait_dag_run_until_finished` authorized the target Dag without its team, unlike every other authorization site. In multi-team mode with a team-aware auth manager, an authenticated user in one team could trigger Dag runs belonging to another team, supplying their own `dag_run_id` and `conf`, and could read another team's XCom values. Deployments using the FAB auth manager are unaffected. Users are advised to upgrade to apache-airflow 3.3.1 or later.

In Apache Airflow, the Task SDK did not mask the contents of a Variable whose JSON value is a list, so secrets stored in that shape appeared in cleartext in task logs and in the Rendered Templates UI. Masking was applied only when the deserialized value was a string or a dict; a list at the top level matched neither and was returned unmasked. Any authenticated user able to read the logs or rendered templates of a task that references such a Variable could recover the values, with no special configuration required. This is the list-shaped counterpart of CVE-2026-59244, whose fix covered the dict case only, so deployments that upgraded in response to that advisory remain affected and must upgrade again. Users are advised to upgrade to apache-airflow 3.3.1 or later.

Apache Airflow wrote Variable values and Connection `extra` contents to the audit log in cleartext when submitted through bulk endpoints (`PATCH /api/v2/variables` and `PATCH /api/v2/connections`). The audit-log masking only recognized top-level request fields, and a bulk request nests entities two levels below, so no masking was applied. Any authenticated user with audit-log read access (not necessarily holding Variables or Connections read permissions) could recover those secrets verbatim, and the Connection `extra` copy is stored unencrypted in the log while the connection table encrypts it.

Apache Airflow's Backfill API authorized a request against a Dag id supplied by the caller whenever the `backfill_id` path segment failed to parse. The authorization dependency parsed it with `int()` while the route handler parsed it as pydantic's `NonNegativeInt`, which accepts values `int()` rejects (`1.0` coerces to `1`); FastAPI resolves dependencies before endpoint validation, so the two acted on different Dags. An authenticated user holding edit permission on any single Dag could therefore read, pause and cancel backfills belonging to any other Dag, including moving another Dag's queued runs to `failed`. No non-default configuration is required and backfill ids are sequential, so finding a target is trivial. Users are advised to upgrade to apache-airflow 3.3.1 or later, which parses the backfill id with the same type the routes declare.

In Apache Airflow, the environment-variable secrets backend resolved a team-scoped Connection or Variable from the wrong team's scope. The guard meant to prevent this only ran when no team scope was supplied, and its pattern could not match a team name containing an underscore. In multi-team mode an authenticated user of one team could resolve another team's Connection and authenticate outward with that team's credentials.

Apache Airflow's Task SDK rebuilt a `Callback` object from serialized data by re-running its constructor, which imports the module named by the stored callback path. Because `SyncCallback` is itself an Airflow class it passes the default `allowed_deserialization_classes` allow-list, so tightening that setting does not help. A Dag author — who controls a task instance's `next_kwargs` through the task execution API — can therefore cause an arbitrary module to be imported inside the scheduler process, when the scheduler's `awaiting_input` timeout sweep deserializes that value. No non-default configuration is required; the sweep runs unconditionally. Versions before 3.3.0 are not affected: the class existed, but the scheduler sweep that reaches it did not. This is a separate code path from CVE-2026-58076 and CVE-2026-67260, which cover different gadgets reaching deserialization — applying either of those fixes does not address this one. Users are advised to upgrade to apache-airflow 3.3.1 or later.

Apache Airflow 3.3.0 has a vulnerability in the human-in-the-loop task handling, where deserialization of next_kwargs without an allow-list allows a DAG author to import arbitrary modules and instantiate objects in the scheduler process or terminate the scheduler job. Upgrade to 3.3.1 or later is required.