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Apache Airflow Deserialization Flaws Allow Arbitrary Class Construction

1 source · 5 articlesFirst reported Updated ()
What's new

First merged summary.

Merged summary · x-ai/grok-4.7 · rewritten as coverage arrivesSummaries by Vani AI

Multiple deserialization vulnerabilities in Apache Airflow let Dag authors construct arbitrary classes in scheduler, API, and Triggerer processes before version 3.4.0.

Apache Airflow contains several deserialization flaws in its handling of deadline alerts, XCom values, next_kwargs, and Dag run conf. These issues let malicious Dag authors craft payloads that instantiate classes from allow-lists, including Airflow's own, inside scheduler, API server, and Triggerer processes. The vulnerabilities affect versions from 3.0.0 to 3.3.2. All are fixed in version 3.4.0. Users are advised to upgrade immediately.

Key facts
  • Dag authors can build arbitrary classes in scheduler and API servers
  • Scheduler fully deserializes task-controlled XCom during dependency checks
  • next_kwargs deserialization bypasses dict check in versions 3.3.0-3.3.2
  • Reserved keys in Dag run conf crash scheduler or rebuild objects in Triggerer
  • set_xcom skips reserved-key check for task-written XComs on API server
  • Affects Apache Airflow 3.0.0 to 3.3.2; fixed in 3.4.0
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Timeline

dated events in the reporting · oldest first
  1. Nov 9, 2026oss-security discloses CVE-2026-82337 Apache Airflow deserialization flaw · oss-security
  2. Nov 9, 2026oss-security discloses CVE-2026-86829 XCom deserialization in scheduler · oss-security
  3. Nov 9, 2026oss-security discloses CVE-2026-96285 next_kwargs deserialization bypass · oss-security
  4. Nov 9, 2026oss-security discloses CVE-2026-111395 reserved keys in Dag run conf · oss-security
  5. Nov 9, 2026oss-security discloses CVE-2026-111421 set_xcom XCom deserialization on API · oss-security

What each outlet adds

beyond the shared facts
  • oss-securityAll five reports on same day detail related Apache Airflow deserialization issues with version-specific fixes
CVEs
CVE-2026-86829CVE-2026-82337CVE-2026-111421CVE-2026-96285CVE-2026-111395
Vendors
Apache
Products
Airflow

Coverage

oldest first · one row per article · UTC
  1. · 2d ago oss-securityFirst report

    Apache Airflow before 3.4.0 allows deserialization of DeadlineAlert fields (CVE-2026-82337)

    Dag authors can construct arbitrary classes in scheduler and API server processes.

  2. · 2d ago oss-security

    Apache Airflow scheduler deserializes task-controlled XCom values (CVE-2026-86829)

    Dag authors control XCom values that the scheduler fully deserializes during dependency evaluation.

  3. · 2d ago oss-security

    Apache Airflow scheduler deserializes next_kwargs before dict check (CVE-2026-96285)

    Deserialization of next_kwargs occurs before the dictionary check, allowing reconstruction of permitted nested objects in the scheduler.

  4. · 2d ago oss-security

    Apache Airflow mishandles reserved keys in Dag run conf triggering scheduler crashes or Triggerer object reconstruction…

    Reserved serialization keys in Dag run conf can crash the scheduler repeatedly or be rebuilt as objects inside the Triggerer via deadline callbacks in versions before 3.4.0.

  5. · 2d ago oss-security

    Apache Airflow skips reserved-key check allowing task XComs to instantiate airflow classes (CVE-2026-111421)

    A task author can write an XCom that causes the Execution API to deserialize and instantiate airflow.* classes in versions before 3.4.0.

Vulnerabilities in this story

All
CVEVulnerabilityCVSSEPSSSignalsPublished
CVE-2026-111421
+4 related CVEs
CVE-2026-86829CVE-2026-111395CVE-2026-82337CVE-2026-96285
Deserialization RCE in Apache Airflow Execution API
8.8
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