CVE-2026-16103
Last modified
CVE-2026-16103 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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. EPSS estimates a 0.34% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Redhat | Build Of Keycloak | All versions |
References
- https://access.redhat.com/security/cve/CVE-2026-16103Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2501736Issue Tracking, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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