Incomplete event deletion in MISP leaves orphaned sensitive records

MISP contains a data integrity flaw in its event deletion logic. When a user deletes an event, several associated records are not removed from the database, leaving them as orphaned entries. The affected record types include event report tags, event graph entries, proposal (shadow attribute) correlations, fuzzy ssdeep correlation chunks, and attachment scan results. These orphaned records may contain sensitive threat intelligence data such as correlation mappings, scan results, and report metadata that should have been removed along with the parent event. Their persistence beyond the intended deletion lifecycle creates a risk of unintended data retention and potential information exposure if the records are reachable through other application queries or administrative interfaces. Preconditions: - An authenticated user with sufficient privileges to delete events in MISP. - The event must have associated reports, graphs, correlations, ssdeep chunks, or attachment scan results. Impact: - Residual sensitive data persists in the database after the parent event is deleted. - Accumulation of orphaned records over time may contribute to storage bloat. - Orphaned records may be inadvertently exposed through other data-access paths that do not validate the existence of the parent event. Affected versions: <2.5.48