Apache Airflow: Execution API: set_xcom skips the reserved-key check, so task-written XComs instantiate airflow.* classes on the API server

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-111421
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-09 10:17:03 UTC
Updated2026-11-09 15:17:05 UTC
DescriptionApache Airflow's Task Execution API stored XCom values written by a task without the reserved-key check applied elsewhere, so a Dag author's task could write an XCom that, when a user later viewed it through the API with deserialization enabled, made the API server instantiate classes from the `airflow.*` namespace with arguments the Dag author chose. This is an incomplete fix for CVE-2026-59242: users who applied that fix in apache-airflow 3.3.1 remain affected through this route and should upgrade to apache-airflow 3.4.0 or later.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from ADP

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

Problem Types: CWE-502 | CWE-502 CWE-502: Deserialization of Untrusted Data

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Airflow affected 3.0.0 3.4.0 semver Not specified

References

ReferenceSourceLinkTags
github.com/apache/airflow/pull/74829 [email protected] github.com
www.cve.org/CVERecord [email protected] www.cve.org
github.com/apache/airflow/pull/72718 [email protected] github.com
lists.apache.org/thread.html/pwdwx354tv0x3m8wzfhh59r6wyztj2lk [email protected] lists.apache.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Qi Qin of depthfirst (en)

CNA: Hama1cco (en)

CNA: Zhixi "Jace" Sun, independent security researcher (en)

CNA: Michael Lip (theluckystrike) (en)

CNA: Jarek Potiuk (en)

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