A vulnerability was found in the Keycloak Server. The Keycloak Server is vulnerable to a denial of service (DoS) attack due to improper handling of proxy headers. When Keycloak is configured to accept incoming proxy headers, it may accept non-IP values, such as obfuscated identifiers, without proper validation. This issue can lead to costly DNS resolution operations, which an attacker could exploit to tie up IO threads and potentially cause a denial of service.
The attacker must have access to send requests to a Keycloak instance that is configured to accept proxy headers, specifically when reverse proxies do not overwrite incoming headers, and Keycloak is configured to trust these headers.

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

CWE-444

https://access.redhat.com/errata/RHSA-2024:10175

https://access.redhat.com/errata/RHSA-2024:10176

https://access.redhat.com/errata/RHSA-2024:10177

https://access.redhat.com/errata/RHSA-2024:10178

https://access.redhat.com/security/cve/CVE-2024-9666

https://bugzilla.redhat.com/show_bug.cgi?id=2317440