According to a joint investigation by the Guardian and the Washington Post, Israel has prevented Ukraine and Estonia from purchasing Pegasus spy software from the Israeli company NSO Group, fearing that the sale of such a sophisticated (hacking) tool would enrage Russia.

According to experts, Ukrainian officials have been attempting to persuade Israel to grant them permission to use the spyware since 2019, and possibly earlier. However, the NSO group, whose product exports are approved by the Israeli Ministry of Defense, was barred from selling Pegasus to Ukraine. In the case of Estonia, the country was in the process of purchasing the spyware, but the sale did not go through after Israel was notified by Russia of Estonia's plans to use Pegasus against Russia, according to the New York Times. 
NSO Group told The Guardian it 'continues to be subjected to inaccurate media reports regarding alleged clients, which are based on hearsay, political innuendo and untruths.'