CentreStack versions before 17.5 contain a critical hardcoded cryptographic key vulnerability tracked as CVE-2026-54363. The flaw stems from a static SysNumber value used as entropy for AccessTicket.Encrypt() and AccessTicket.Decrypt() functions shared across all installations. Unauthenticated attackers can exploit this to forge arbitrary encrypted tokens and craft valid x-glad-auth headers. By leveraging these forged tokens, attackers can call privileged API endpoints such as acquiretenantbackuptoken to obtain a domain administrator IdentityTicket. This ultimately enables a complete unauthenticated remote code execution chain, making it a critical severity vulnerability. Organizations running CentreStack should upgrade to version 17.5 or later immediately.