CVE-2026-16103 Details
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.
A vulnerability exists in the keycloak-services component of Keycloak, stemming from an incomplete fix for CVE-2026-9798. While brute-force protection was added to the Client-Initiated Backchannel Authentication (CIBA) initiation handler, it was not implemented in the token redemption handler. This oversight 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, as long as the authentication request was initiated before the lockout and approved by the user.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 17, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2026-16103 | [email protected] | Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2501736 | [email protected] | Issue TrackingVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-305 | Authentication Bypass by Primary Weakness | [email protected] |
| CWE-841 | Improper Enforcement of Behavioral Workflow | CISA-ADP |
Affected Products
| Product | Versions |
|---|---|
| redhat build of keycloak | All versions |
CPE
Remediation
| |
Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 31, 2026 | CVE Modified | [email protected] |
| Aug 6, 2026 | Initial Analysis | [email protected] |
| Jul 21, 2026 | CVE Modified | CISA-ADP |
| Jul 17, 2026 | New CVE Received | [email protected] |
| Jul 17, 2026 | CVE Modified | CISA-ADP |