What’s Vulnerable › Vulnerabilities

CVE-2026-59242: Apache Airflow: Arbitrary airflow.* class instantiation on the API server via the XCom deserialize endpoint

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-12 · updated 2026-10-24
• Weakness: CWE-502

Description

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.

Affected products

• Apache Airflow: before 3.3.1 — fixed in 3.3.1

How to fix

Upgrade to a fixed version: Apache Airflow 3.3.1. Check the vendor advisory for mitigations.

References

• https://github.com/apache/airflow/pull/69378
• https://lists.apache.org/thread/dm0520yhh4mn7qknyoh45r2w6c5qg2mg
• http://www.openwall.com/lists/oss-security/2026/08/12/6

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