Here is UK specific answer, and as they point out, if you sell to some one knowing they are going to commit a crime with it, you can be considered an accomplic

Here is UK specific answer, and as they point out, if you sell to some one knowing they are going to commit a crime with it, you can be considered an accomplice in many jurisdictions. https://law.stackexchange.com/questions/11552/is-it-illegal-to-create-and-sell-a-exploit-of-a-zero-day-vulnerability https://law.stackexchange.com/questions/11552/is-it-illegal-...