CVE-2026-59243: The FAB auth manager's Azure AD OAuth login defaulted `verify_signature=False` when decoding the ID token, so

Q: How do I fix CVE-2026-59243?

apache-airflow-providers-fab: upgrade to 3.7.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-59243 being exploited?

CVE-2026-59243 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-59243 affect?

CVE-2026-59243 affects apache-airflow-providers-fab. Severity is critical (CVSS 9.8). 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 i

Q: How urgent is CVE-2026-59243?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-59243 is a critical-severity flaw (CVSS 9.8) affecting apache-airflow-providers-fab. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 pa

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-347
Published	2026-07-29
Last modified	2026-10-23

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-29 10:16 UTCPublished CVE record published
2026-10-23 23:10 UTCUpdated Record last modified

apache apache-airflow-providers-fab UPGRADE

Affected: < 3.7.3

Fixed in: 3.7.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy apache-airflow-providers-fab || rpm -q apache-airflow-providers-fab || apache-airflow-providers-fab --version

2. UPGRADE to 3.7.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade apache-airflow-providers-fab

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade apache-airflow-providers-fab

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora 46 · python-openslide · FIXED · 1.4.7-1.fc46 · FEDORA-2026-336bea884e · source

sudo dnf upgrade --advisory=FEDORA-2026-336bea884e

Fedora ELN · valgrind · FIXED · 3.28.0-1.eln159 · FEDORA-2026-c593ef1d15 · source

sudo dnf upgrade --advisory=FEDORA-2026-c593ef1d15

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: 0xdak/CVE-2026-59243_exploit (1 stars)
GitHub PoC: MalHyuk/CVE-2026-59243 (0 stars)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-59243?

apache-airflow-providers-fab: upgrade to 3.7.3. Exact commands for each OS are on this page.

Is CVE-2026-59243 being exploited?

CVE-2026-59243 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-59243 affect?

CVE-2026-59243 affects apache-airflow-providers-fab. Severity is critical (CVSS 9.8). 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 i

How urgent is CVE-2026-59243?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Azure vulnerabilities

References

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