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CVE-2026-86466

HIGH 8.1 ALL-YEARS

Published 2026-09-16 · Last modified 2026-09-17 · apache · NVD: Analyzed

Apache Airflow FAB provider: the Authentik OAuth path in the FAB auth manager does not validate the issuer or audience claims of the id_token it accepts. An attacker holding a token that the same Authentik identity provider minted for a different client application can present it to Airflow and be authenticated as the user it names, because the audience claim is never checked. Affects deployments using the FAB auth manager with Authentik OAuth where the same Authentik instance also serves other applications; the attacker needs a valid token for any of those other applications, not for Airflow. CVE-2026-75156 corrected the same missing validation on the Azure AD path in this file; the Authentik path was left unchanged and is fixed here. Deployments that applied the CVE-2026-75156 fix and use Authentik must also upgrade for this one. Users of apache-airflow-providers-fab are recommended to upgrade to version 3.9.0 or later, which fixes the issue.

ELEVATED IMPACT

Severe if exploited (CVSS 8.1), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 29th percentile

○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.1CVSS 3.1 · HIGH · ADP

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.

Affected

Vendors Apache Software Foundation Apache

Products Apache Airflow Fab Provider Apache Airflow Providers Fab

Weakness (CWE)

  • CWE-346: : Origin Validation Error

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
ApacheApache Airflow Providers Fab< 3.9.0

All CVSS metrics

  • HIGH 8.1 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
  • HIGH 8.1 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

References

Patches & mitigations

Advisories

Sources: NVD · CVE.org · EPSS