CVE-2026-74864

sogo_yhn configures SOGo with a parameter that forces requests with the HTTP header "x-webobjects-remote-user" to be treated as sent by a verified user without performing password validation. Since Nginx does not strip this header, any client can supply it arbitrarily and gain access as any user, including a privileged user, without providing a password. This issue was fixed in version 5.8.0~ynh9.

An attacker can impersonate any user, including an administrator, without authentication, leading to full system compromise.

Update sogo_yhn to version 5.8.0~ynh9 or later to remove the header-based authentication bypass.