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 hardcoded key to forge arbitrary encrypted tokens and craft valid x-glad-auth headers. By calling privileged API endpoints such as acquiretenantbackuptoken, attackers can obtain a domain administrator IdentityTicket. This enables a complete unauthenticated remote code execution chain, representing a critical risk to all unpatched CentreStack deployments. The vulnerability affects all installations due to the shared static key, making it a systemic risk rather than an instance-specific one. Organizations running CentreStack should immediately upgrade to version 17.5 or later.