CVE-2026-54730: authentik: Authentication Flow Bypass via Unguarded challenge_valid() in AuthenticatorEndpointGDTCStage and GoogleChromeStageView
authentik is an open-source identity provider. Prior to 2026.2.6 and 2026.5.5, the enterprise Google Chrome device-trust stages advance the flow without confirming that the out-of-band device attestation actually ran. Affected enterprise deployments place either a Google Chrome Endpoint stage with mode set to REQUIRED or the deprecated Google Chrome Device Trust Connector stage in an authentication flow. The device attestation occurs in a verification iframe that calls the Google Verified Access API and records the verified device on success, but the vulnerable stages treat the flow as passed as soon as the stage is submitted. An attacker who can reach such a stage, including after primary username and password authentication, can skip the verification iframe and authenticate from a device that was never verified. Where device trust is the only additional factor, that protection is fully bypassed, while other configured factors remain in force. This issue is fixed in versions 2026.2.6 and 2026.5.5.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Google Chrome device-trust stagesto a version that resolves this vulnerability.Fixed in 2026.2.6 - Upgrade
Upgrade
Google Chrome device-trust stagesto a version that resolves this vulnerability.Fixed in 2026.5.5 - Configuration
Ensure the Google Chrome Endpoint stage is updated to a non-vulnerable version; the issue affects enterprise deployments where a Google Chrome Endpoint stage has mode set to REQUIRED.
Google Chrome Endpoint stage mode = REQUIRED
Event History
Frequently Asked Questions
Which deployments should be prioritized for triage?
Enterprise deployments are affected only when an authentication flow includes either a Google Chrome Endpoint stage configured with mode REQUIRED or the deprecated Google Chrome Device Trust Connector stage. Deployments without either stage in a flow are not identified as affected.
What does an attacker need to exploit the bypass?
An attacker must be able to reach the affected stage, potentially after completing primary username and password authentication. They can submit the stage without running the verification iframe, allowing authentication from a device that has not been verified.
Do other factors in the authentication flow still provide protection?
If device trust is the only additional factor in the flow, it is fully bypassed. Any other authentication factors configured in the flow still remain required.
What is the remediation?
Upgrade to version 2026.2.6 or 2026.5.5. If upgrading is not immediately possible, the provided information does not specify a workaround; prioritize removing or avoiding the affected device-trust stages in authentication flows where feasible.