Information Exposure Through an Error Message in Keycloak - CVE-2026-4633
Published: September 10, 2026
Vulnerability identifier: #VU148943
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-4633
CWE-ID: CWE-209
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose user information.
The vulnerability exists due to generation of error messages containing sensitive information in Keycloak\'s identity-first login flow when Organizations are enabled. A remote attacker can exploit differential error messages to disclose user information.
Exploitation enables user enumeration.
Affected software
Keycloak
How to mitigate CVE-2026-4633
Install security update from vendor's website.
Keycloak - addressed in versions 26.4.12, 26.6.1