SpiceDB is an open source, Google Zanzibar-inspired database for creating and managing security-critical application permissions. Integer overflow in chunking helper causes dispatching to miss elements or panic.  Any SpiceDB cluster with any schema where a resource being checked has more than 65535 relationships for the same resource and subject type is affected by this problem.  The CheckPermission, BulkCheckPermission, and LookupSubjects API methods are affected. This vulnerability is fixed in 1.29.2.