What is CVE-2026-40109?

CVE-2026-40109 is a low-severity vulnerability in Fluxcd Notification-controller, classified under Improper Authentication. CVSS score: 3.1/10. Published 2026-04-09.

How severe is CVE-2026-40109?

Low severity. CVSS v3 base score is 3.1 out of 10.

Auth bypass in Fluxcd Notification-controller

CVE-2026-40109

Flux notification-controller is the event forwarder and notification dispatcher for the GitOps Toolkit controllers. Prior to 1.8.3, the gcr Receiver type in Flux notification-controller does not validate the email claim of Google OIDC toke…

Vulnerability class: Broken Authentication

EPSS: 0.000 (5.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N.

Affected products

Fluxcd Notification-controller — versions < 1.8.3

Weakness classification (CWE)

References

https://github.com/fluxcd/notification-controller/security/advisories/GHSA-h9cx-xjg6-5v2w (x_refsource_CONFIRM)
https://github.com/fluxcd/notification-controller/pull/1279 (x_refsource_MISC)
https://github.com/fluxcd/notification-controller/releases/tag/v1.8.3 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-40109?: CVE-2026-40109 is a low-severity vulnerability in Fluxcd Notification-controller, classified under Improper Authentication. CVSS score: 3.1/10. Published 2026-04-09.
How severe is CVE-2026-40109?: Low severity. CVSS v3 base score is 3.1 out of 10.