CVE-2026-86829: Insecure Deserialization (CVSS 8.8)

Description

Apache Airflow's scheduler fully deserializes XCom values written by task code while evaluating task dependencies. A Dag author, who controls what a task writes to XCom, therefore controls data that is deserialized inside the scheduler process - a context the Airflow security model reserves for code installed by the Deployment Manager, above the worker-scoped execution capability a Dag author is documented to have. Deployments that treat Dag authors as less trusted than Deployment Managers are affected, and the scheduler must be evaluating a task dependency that reads a task-written XCom value. Users of apache-airflow are recommended to upgrade to version 3.4.0 or later, which restricts dependency evaluation to primitive XCom values.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

References

Other References

https://github.com/apache/airflow/pull/72718 https://lists.apache.org/thread.html/2qbt7qnclrlxtg3f1b685533r3mvk9hv http://www.openwall.com/lists/oss-security/2026/11/09/9

Frequently Asked Questions

What is CVE-2026-86829? +

Apache Airflow's scheduler fully deserializes XCom values written by task code while evaluating task dependencies. A Dag author, who controls what a task writes to XCom, therefore controls data that is deserialized inside the scheduler process - a context the Airflow security model reserves for code installed by the Deployment Manager, above the worker-scoped execution capability a Dag author is documented to have. Deployments that treat Dag authors as less trusted than Deployment Managers are affected, and the scheduler must be evaluating a task dependency that reads a task-written XCom value. Users of apache-airflow are recommended to upgrade to version 3.4.0 or later, which restricts dependency evaluation to primitive XCom values. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-86829? +

CVE-2026-86829 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-86829? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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