MISP contains an improper input validation vulnerability in the decaying model import...

MISP contains an improper input validation vulnerability in the decaying model import functionality. The import endpoint was intended to create a new decaying model belonging exclusively to the importing user's organisation, with the default flag forced to off.

However, the application stripped only the top-level id and uuid fields and pinned org_id and default on the outer array before saving the data flat. A user with decaying-model permissions could supply a nested model key carrying its own primary key, organisation identifier, and default flag, which bypassed those guards during the save operation.

Impact:

• A user with perm_decaying could overwrite an existing decaying model belonging to another organisation in place, altering its name, formula, parameters, or ownership.

• A user could create or modify a model flagged as the organisation default, affecting scoring behaviour for other users.

• A user could reassign a model's organisation to an arbitrary value.

Preconditions:

• Authenticated user with decaying-model permission (perm_decaying).

• Network access to the MISP instance.

Affected: <2.5.48.