CVE-2026-19607: Auth Bypass (CVSS 5.3)

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.

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CVSS v3.1 Score

5.3

MEDIUM

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

Weakness Type (CWE)

CWE-287 Improper Authentication

References

Other References

https://access.redhat.com/errata/RHSA-2026:68276 https://access.redhat.com/errata/RHSA-2026:68277 https://access.redhat.com/errata/RHSA-2026:68278 https://access.redhat.com/errata/RHSA-2026:68280 https://access.redhat.com/security/cve/CVE-2026-19607 https://bugzilla.redhat.com/show_bug.cgi?id=2514529

Frequently Asked Questions

What is CVE-2026-19607? +

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-19607? +

CVE-2026-19607 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-19607? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-19607