MISP Correlation Authorization Bypass Exposes Restricted Event and Attribute Data

MISP contains an authorization flaw in its correlation handling during attribute searches. When a user performs an attribute search that triggers correlation lookups, the system authorized access to correlated attributes and events based on a stale distribution snapshot stored on the correlation row rather than the live event access control list.

Because the correlation row's distribution columns are a point-in-time copy that lacks a published flag, the authorization check becomes incorrect when an event is subsequently restricted (for example, its sharing group is changed or it is unpublished). As a result, an authenticated user could retrieve attributes and event details belonging to events they no longer have permission to view.

Preconditions:

• An authenticated user with at least read access to some events in the instance.

• The existence of correlations between events, at least one of which has been restricted after the correlation was created.

Impact:

• Confidentiality: exposure of attribute values and event metadata that the user is not authorized to access.

Affected versions: MISP prior to v2.5.48.