VulnerabilityPublished 9 Nov 2026

CVE-2026-86829: Apache Airflow · Deserialization of Untrusted Data

Affects Apache AirflowSource CVE Database V5

Compare

Not known to be exploited : upgrade to 3.4.0 soon.

Data as of 9 Nov 2026, 10:19 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 3.4.0

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Apache Airflow and apache-airflow-core to 3.4.0.

Affected software

Product	Affected	Fixed in
Apache Airflowapache-airflow-core	Affected <3.4.0	Fixed in 3.4.0
PyPIapache-airflow-core`pkg:pypi/apache-airflow-core`Other threats	Affected <3.4.0	Fixed in 3.4.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should upgrade Apache Airflow to version 3.4.0 or later, where the scheduler restricts dependency evaluation to primitive XCom values, eliminating unsafe deserialization. No other mitigation is indicated by the vendor advisory.

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.

Impact

The vulnerability allows a Dag author to influence the scheduler process by controlling deserialized data, potentially leading to privilege escalation or unauthorized code execution within the scheduler context. This breaks the security model that separates Dag author capabilities from Deployment Manager privileges. The impact depends on deployment trust boundaries and whether the scheduler evaluates task dependencies that read task-written XCom values.

Summary

Apache Airflow's scheduler deserializes XCom values created by task code during task dependency evaluation. Since Dag authors control the content of these XCom values, they can supply malicious serialized data that is deserialized in the scheduler process, which runs with higher privileges than the task execution environment. This creates a security risk in deployments where Dag authors are less trusted than Deployment Managers. The vulnerability is identified as CWE-502 (Deserialization of Untrusted Data). The flaw affects all versions from initial releases up to but not including 3.4.0. The issue is resolved in version 3.4.0 by limiting dependency evaluation to primitive XCom values, preventing unsafe deserialization.

CWE-502Deserialization of Untrusted Data (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #15OWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Architecture and Design · Implementation
If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
Implementation
When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
Implementation
Explicitly define a final object() to prevent deserialization.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
XML Security (opens in a new tab)
XML External Entity Prevention (opens in a new tab)
Software Supply Chain Security (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.2 (opens in a new tab)
V5.5.3 (opens in a new tab)
V5.5.1 (opens in a new tab)
Attack patterns
Object Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Nov 2026, 10:05 UTC

WeaknessesCWE-502

Technical details

References

Community reviews

Related threats