MISP Event Synchronization Exposes Non-Exportable Tags on Remote Instances

In MISP, the event synchronization process contained a logic error in the preparation of event reports for remote push. The filtering of non-exportable tags was applied only once after the iteration over all reports, rather than to each individual report.

As a result:

- All reports except the last one in the set were pushed to the remote MISP instance with their non-exportable tags intact, effectively disclosing restricted tag information to the receiving instance.

- When the last report in the set was withheld (empty), a null report was pushed, causing the remote instance to fail saving the event.

This issue affects any MISP instance configured to push events with multiple reports to a remote server via synchronization.

Affected: <2.5.48.