It is possible that a conviction registered in the Swiss criminal record be communicated to a foreign state. Several hypotheses are possible.
The first is when the competent authorities of the foreign state expressly request the Swiss authorities to do so. However, this presupposes that the foreign authorities have reason to believe that you may have been convicted in Switzerland.
The second is where an international agreement between Switzerland and other States expressly provides for the automatic communication of convictions. Such an agreement exists between Switzerland and other European states. However, the criterion is that of nationality. Thus, the foreign State will be informed of the entries in the Swiss criminal record of persons who are nationals of that State. For example, the criminal record of a German convicted in Switzerland will automatically be communicated to Germany. On the other hand, the States in which the person convicted in Switzerland resides or has a residence permit will not, with some exceptions, receive spontaneous notification of the Swiss conviction.
