CVE-2026-93594: high-severity vulnerability in ArcadeData arcadedb

ArcadeDB (Maven artifact com.arcadedb:arcadedb-engine) through 26.8.1 enforces its per-type/per-record access-control rules only in LocalBucket, keyed on file id. Query-execution paths that reach record data through LSM index files or the TimeSeries engine never invoke that permission check, so an authenticated user who is denied readRecord/deleteRecord on a type can still, with a single ordinary SQL statement, read the type's indexed key values and record IDs (e.g. SELECT key, rid FROM INDEX:Type[field]), read MAX/MIN values via the index shortcut, read and count TimeSeries samples, learn the type's record count, and delete index entries (DELETE FROM INDEX:Type[field]), which desynchronizes the index from the data and can defeat unique constraints. Index and type names needed for exploitation are discoverable because SELECT FROM schema:indexes is unfiltered. The issue affects both embedded and server deployments and all transports (HTTP, Bolt, Postgres, Gremlin) once a principal is bound. Fixed in 26.9.1.