CVE-2026-59243: apache software foundation apache airflow fab provider
Vulnerability summary
CVE-2026-59243 is a critical (CVSS 9.8) vulnerability in apache software foundation apache airflow fab provider. EPSS estimates a 0.64% chance of exploitation in the next 30 days, higher than 49.7% of scored vulnerabilities.
Timeline
- 29-07-2026PublishedVulnerability first disclosed.
- 16-09-2026Last modifiedVulnerability information updated.
Description
The FAB auth manager's Azure AD OAuth login defaulted `verify_signature=False` when decoding the ID token, so an attacker able to present a forged or unsigned (`alg:none`) ID token to the OAuth callback could bypass authentication and log in as an arbitrary user, including one holding the Admin role (CWE-347). Deployments running the FAB auth manager with the Azure AD OAuth login path under its default configuration are affected; the Authentik path already defaulted to `True`. This issue affects `apache-airflow-providers-fab` before 3.7.3. Users are advised to upgrade to `apache-airflow-providers-fab` 3.7.3, which defaults `verify_signature=True`.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.64%
Chance of exploitation in the next 30 days
Percentile
50%
Versus all other CVEs
30-day change
+0.20 pp
From 0.45% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Apache1 product
- apache-airflow-providers-fab< 3.7.3
Apache software foundation1 product
- apache airflow fab provider< 3.7.3
2 vendors · 2 products