CVE-2026-9798
When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection.
Does this matter?
Lower severity and a low EPSS score (0.35%). Track it; it rarely justifies an emergency change on its own.
Description
A flaw was found in Keycloak, an open-source identity and access management solution. When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection. This allows continued authentication attempts and token issuance even when the account should be locked, potentially enabling further unauthorized access attempts.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
- EPSS
- 0.35% probability · 28th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-305
- Affected
- redhat/build of keycloak
- Source
- secalert@redhat.com
References
- https://access.redhat.com/errata/RHSA-2026:50846
- https://access.redhat.com/errata/RHSA-2026:50847
- https://access.redhat.com/errata/RHSA-2026:50848
- https://access.redhat.com/errata/RHSA-2026:50849
- https://access.redhat.com/security/cve/CVE-2026-9798Mitigation, Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2482470Issue Tracking, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.