Keycloak-services: keycloak-services: ciba confidential-only contract not enforced for public clients

A flaw was found in the Client-Initiated Backchannel Authentication CIBA implementation within the keycloak-services component of Keycloak. This component handles advanced authentication flows where a client initiates a login on behalf of a user. The issue occurs because Keycloak fails to verify that a client is authorized to use the CIBA flow, allowing public clients to bypass security requirements. An attacker could use this flaw to trick a user into approving a login request, eventually gaining full access to the users account without needing a client secret.

Source published

12 Oct 2026 06:18:08 UTC

Source modified

15 Oct 2026 15:16:24 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N