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Apache Airflow Task SDK Callback deserialization can import arbitrary modules in the scheduler

High severity GitHub Reviewed Published Aug 12, 2026 to the GitHub Advisory Database • Updated Oct 2, 2026

Package

pip apache-airflow (pip)

Affected versions

>= 3.3.0, < 3.3.1

Patched versions

3.3.1

Description

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.

References

Published by the National Vulnerability Database Aug 12, 2026
Published to the GitHub Advisory Database Aug 12, 2026
Reviewed Oct 2, 2026
Last updated Oct 2, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(49th percentile)

Weaknesses

Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. Learn more on MITRE.

CVE ID

CVE-2026-67587

GHSA ID

GHSA-2qjv-p2gc-mjg2

Source code

Credits

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