CVE-2026-111421

Summary

Apache Airflow's Task Execution API failed to enforce the reserved-key check on XCom values written by tasks, allowing malicious DAG authors to inject deserialized objects via crafted XComs. When users viewed these XComs through the API with deserialization enabled, the Airflow server instantiated arbitrary classes from the airflow.* namespace using attacker-controlled arguments, enabling remote code execution.

Exploitability

Exploitation requires low-privilege access (PR:L) as a DAG author who can write tasks that store XComs; no user interaction or complex conditions are needed beyond enabling deserialization in the API.

Blast radius

Successful exploitation grants full compromise of the Airflow API server (CIA high impact), potentially affecting all downstream systems accessible to the Airflow service account.

Detection

No reliable host or network indicator is derivable from the published description.

Prioritized remediation

Upgrade to apache-airflow 3.4.0 or later, which fully addresses this incomplete fix for CVE-2026-59242.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.