Apache Airflow: Authorization bypass in the Backfill API through conflicting interpretations of the backfill id

Summary

CVECVE-2026-68968
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-12 16:17:19 UTC
Updated2026-08-12 16:17:19 UTC
DescriptionApache Airflow's Backfill API authorized a request against a Dag id supplied by the caller whenever the `backfill_id` path segment failed to parse. The authorization dependency parsed it with `int()` while the route handler parsed it as pydantic's `NonNegativeInt`, which accepts values `int()` rejects (`1.0` coerces to `1`); FastAPI resolves dependencies before endpoint validation, so the two acted on different Dags. An authenticated user holding edit permission on any single Dag could therefore read, pause and cancel backfills belonging to any other Dag, including moving another Dag's queued runs to `failed`. No non-default configuration is required and backfill ids are sequential, so finding a target is trivial. Users are advised to upgrade to apache-airflow 3.3.1 or later, which parses the backfill id with the same type the routes declare.

Risk And Classification

Problem Types: CWE-436 | CWE-436 CWE-436: Interpretation Conflict

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Airflow affected 3.3.1 semver Not specified

References

ReferenceSourceLinkTags
lists.apache.org/thread/f9zmw6xs5b4syhwzbl6fsxm4kf2632ol [email protected] lists.apache.org
github.com/apache/airflow/pull/70889 [email protected] github.com
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: Jarek Potiuk (en)

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