CVE-2026-9798

Keycloak: keycloak: brute-force protection bypass in ciba flow

MEDIUM
4.3
CVSS Score
Published: May 28, 2026 at 04:37 AM UTC
Updated: October 26, 2026 at 12:10 PM UTC
1 product affected across 1 vendorBuild of Keycloak

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions26.4
Vendor states this is fixed in 26.4-22 (unaffected)
Vendor states this is fixed in 26.4.14 (unaffected)
Vendor states this is fixed in 26.4.14-1 (unaffected)
Vendor states this is fixed in 26.6-11 (unaffected)
Vendor states this is fixed in 26.6.5 (unaffected)
Vendor states this is fixed in 26.6.5-1 (unaffected)

References (6)

VDB Entryx_refsource_REDHATMitigationVendor Advisory
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-9798
Issue Trackingx_refsource_REDHATVendor Advisory
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2482470
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:50846
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:50847
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:50848
Vendor Advisoryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/errata/RHSA-2026:50849

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-305

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