CVE-2026-9798 — MEDIUM (4.3)

Vulnerability 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 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

LOW

Integrity

NONE

Availability

NONE

Affected Products

Vendor	Product	Versions
Redhat	Build Of Keycloak	-

Related Weaknesses (CWE)

CWE-305

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-2026-9798MitigationVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2482470Issue TrackingVendor Advisory

FAQ

What is CVE-2026-9798?

CVE-2026-9798 is a vulnerability with a CVSS score of 4.3 (MEDIUM). 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 cre...

How severe is CVE-2026-9798?

CVE-2026-9798 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-9798?

Check the references section above for vendor advisories and patch information. Affected products include: Redhat Build Of Keycloak.