Deserialization of Untrusted Data Affecting apache-airflow-core package, versions [,3.4.0)

Affected versions of this package are vulnerable to Deserialization of Untrusted Data via the scheduler's dependency evaluation path, which fully deserializes XCom values written by task code through XComModel.deserialize_value. The XComDecoder object hook invokes the Airflow serialization module with full=True, meaning any stored dict carrying a __classname__ key is imported and instantiated inside the scheduler process. A DAG author who controls what a task writes to XCom can therefore cause arbitrary class instantiation in the scheduler, a privilege level the Airflow security model reserves for the Deployment Manager rather than DAG authors.

Note: This is only exploitable in deployments where DAG authors are treated as less trusted than Deployment Managers, and only when the scheduler is evaluating a task dependency that reads a task-written XCom value.

Serialization is a process of converting an object into a sequence of bytes which can be persisted to a disk or database or can be sent through streams. The reverse process of creating object from sequence of bytes is called deserialization. Serialization is commonly used for communication (sharing objects between multiple hosts) and persistence (store the object state in a file or a database). It is an integral part of popular protocols like Remote Method Invocation (RMI), Java Management Extension (JMX), Java Messaging System (JMS), Action Message Format (AMF), Java Server Faces (JSF) ViewState, etc.

Deserialization of untrusted data (CWE-502) is when the application deserializes untrusted data without sufficiently verifying that the resulting data will be valid, thus allowing the attacker to control the state or the flow of the execution.

• Apache Security Advisory
• GitHub PR