Medium severity · published Sep 16, 2026
CVE-2026-19607
Keycloak-services: keycloak-services: broker-originated username collision causes account lockout
5.3
CVSS
0.7%
EPSS
No
On KEV
Description
A flaw was found in the first-broker-login flow of the keycloak-services component. This component handles the initial authentication and account linking when a user logs in via an external identity provider. The issue allows an attacker to register a matching username on an external provider to trigger a collision in Keycloak, which results in the legitimate user being locked out of their account.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat build of Keycloak 26.4 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat build of Keycloak 26.6 · Red Hat
All versions, or not specified · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19607
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-19607
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:68276
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:68277
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:68278
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:68280
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-19607
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2514529
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