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Fencer Vulns
medium 5.3

CVE-2026-19607 json

Keycloak-services: keycloak-services: broker-originated username collision causes account lockout

published 2026-09-16 53 d ago modified 2026-09-16 53 d ago also EUVD-2026-80855

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat build of Keycloak 26.4 26.4-26, 26.4.16-2
  • Red Hat Red Hat build of Keycloak 26.6 26.6-20, 26.6.7-3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-19607 updated cvss 5.3

keycloak-services: keycloak-services: Broker-originated username collision causes account lockout

  • Red Hat build of Keycloak 26.4 rhbk/keycloak-rhel9 26.4-26, rhbk/keycloak-rhel9-operator 26.4-26, rhbk/keycloak-operator-bundle 26.4.16-2
    fixed: vendor fix RHSA-2026:68276
  • Red Hat build of Keycloak 26.4.16
    fixed: vendor fix RHSA-2026:68280
  • Red Hat build of Keycloak 26.6 rhbk/keycloak-rhel9 26.6-20, rhbk/keycloak-rhel9-operator 26.6-20, rhbk/keycloak-operator-bundle 26.6.7-3
    fixed: vendor fix RHSA-2026:68277
  • Red Hat build of Keycloak 26.6.7
    fixed: vendor fix RHSA-2026:68278
  • Red Hat Single Sign-On 7 keycloak-services 18.0.3.redhat-00001
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
53 d ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

  • Red Hat Red Hat build of Keycloak 26.4
  • Red Hat Red Hat build of Keycloak 26.4.16
  • Red Hat Red Hat build of Keycloak 26.6
  • Red Hat Red Hat build of Keycloak 26.6.7
  • Red Hat Red Hat Single Sign-On 7

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.