CVE-2026-16103
Keycloak-services: keycloak-services: incomplete fix for ciba brute-force lockout bypass at token redemption
MEDIUM 4.3
At a glance
- Source
- NVD
- EPSS
- EPSS 0.34 % · percentile 28 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- redhat
- NVD status
- Modified
Description
A flaw was found in the keycloak-services component of Keycloak. This issue is an incomplete fix for CVE-2026-9798, where brute-force protection checks were added to the Client-Initiated Backchannel Authentication (CIBA) initiation handler but were omitted from the token redemption handler. This allows an attacker with valid client credentials to obtain access and refresh tokens for a user account that has been locked due to brute-force protection, provided the authentication request was started before the lockout occurred and was approved by the user.
Weaknesses (CWE)
- CWE-305 — Authentication Bypass by Primary Weakness
- CWE-841 — Improper Enforcement of Behavioral Workflow
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N | redhat |
| CVSS 3.1 | MEDIUM 4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N | NVD · secalert@redhat.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-45225
- GCVE · GCVE-0-2026-16103
Affected configurations (NVD CPE)
cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*
Affected products
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |