MISP contains a defect in its event save workflow that prevents the correlation engine from recalculating correlations when an event's distribution level or sharing group is modified.

When a user edits an existing event and changes its distribution or sharing_group_id, the internal before-save hook stored the incoming (new) data rather than the previously persisted values. As a result, the after-save comparison that determines whether a correlation refresh is needed never detected the change, and stale correlations persisted.

Security impact:

- Stale correlations may continue to expose event data to users in a broader sharing group after the event has been moved to a more restrictive group, resulting in unintended information disclosure.

- Conversely, newly relevant correlations may not appear after a distribution widening, degrading the completeness of threat intelligence sharing.

Preconditions:

- An authenticated user with write access to at least one MISP event.

- The user modifies the event's distribution or sharing_group_id field.

Affected versions: <2.5.48