CVE-2026-4981

A flaw was found in Red Hat Advanced Cluster Security (ACS). An unauthenticated remote attacker can exploit a vulnerability in the login interface's OAuth callback endpoint by crafting a malicious URL. This URL, containing unvalidated `error` and `error_uri` parameters, allows the attacker to display arbitrary error messages, leading to content spoofing. Furthermore, the attacker can redirect victims to malicious domains, effectively performing an open redirect under the guise of the trusted application's user interface.