find a loophole

find a loophole (in sth) — найти лазейку/дыру (в законе)

Example: Someone who wants to evade certain taxes might find a loophole that allows them to avoid penalties legally. — Те, кто хочет избежать уплаты определенных налогов, могут найти лазейку ("дыру") в законе, которая поможет им не платить штрафов.

a loophole (in sth) (a mistake in the way a law, contract, etc. has been written which enables people to legally avoid doing something that the law, contract, etc. had intended them to do
a legal loophole)